values that can be loaded: an integer value (IV), a double (NV), a string,
(PV), and another scalar (SV).
-The four routines are:
+The six routines are:
SV* newSViv(IV);
SV* newSVnv(double);
- SV* newSVpv(char*, int);
+ SV* newSVpv(const char*, int);
+ SV* newSVpvn(const char*, int);
+ SV* newSVpvf(const char*, ...);
SV* newSVsv(SV*);
-To change the value of an *already-existing* SV, there are five routines:
+To change the value of an *already-existing* SV, there are seven routines:
void sv_setiv(SV*, IV);
+ void sv_setuv(SV*, UV);
void sv_setnv(SV*, double);
- void sv_setpvn(SV*, char*, int)
- void sv_setpv(SV*, char*);
+ void sv_setpv(SV*, const char*);
+ void sv_setpvn(SV*, const char*, int)
+ void sv_setpvf(SV*, const char*, ...);
+ void sv_setpvfn(SV*, const char*, STRLEN, va_list *, SV **, I32, bool);
void sv_setsv(SV*, SV*);
Notice that you can choose to specify the length of the string to be
-assigned by using C<sv_setpvn> or C<newSVpv>, or you may allow Perl to
-calculate the length by using C<sv_setpv> or by specifying 0 as the second
-argument to C<newSVpv>. Be warned, though, that Perl will determine the
-string's length by using C<strlen>, which depends on the string terminating
-with a NUL character.
-
-All SVs that will contain strings should, but need not, be terminated
-with a NUL character. If it is not NUL-terminated there is a risk of
+assigned by using C<sv_setpvn>, C<newSVpvn>, or C<newSVpv>, or you may
+allow Perl to calculate the length by using C<sv_setpv> or by specifying
+0 as the second argument to C<newSVpv>. Be warned, though, that Perl will
+determine the string's length by using C<strlen>, which depends on the
+string terminating with a NUL character.
+
+The arguments of C<sv_setpvf> are processed like C<sprintf>, and the
+formatted output becomes the value.
+
+C<sv_setpvfn> is an analogue of C<vsprintf>, but it allows you to specify
+either a pointer to a variable argument list or the address and length of
+an array of SVs. The last argument points to a boolean; on return, if that
+boolean is true, then locale-specific information has been used to format
+the string, and the string's contents are therefore untrustworthy (see
+L<perlsec>). This pointer may be NULL if that information is not
+important. Note that this function requires you to specify the length of
+the format.
+
+The C<sv_set*()> functions are not generic enough to operate on values
+that have "magic". See L<Magic Virtual Tables> later in this document.
+
+All SVs that contain strings should be terminated with a NUL character.
+If it is not NUL-terminated there is a risk of
core dumps and corruptions from code which passes the string to C
functions or system calls which expect a NUL-terminated string.
Perl's own functions typically add a trailing NUL for this reason.
SvIV(SV*)
SvNV(SV*)
SvPV(SV*, STRLEN len)
+ SvPV_nolen(SV*)
which will automatically coerce the actual scalar type into an IV, double,
or string.
In the C<SvPV> macro, the length of the string returned is placed into the
-variable C<len> (this is a macro, so you do I<not> use C<&len>). If you do not
-care what the length of the data is, use the global variable C<na>. Remember,
-however, that Perl allows arbitrary strings of data that may both contain
-NULs and might not be terminated by a NUL.
+variable C<len> (this is a macro, so you do I<not> use C<&len>). If you do
+not care what the length of the data is, use the C<SvPV_nolen> macro.
+Historically the C<SvPV> macro with the global variable C<PL_na> has been
+used in this case. But that can be quite inefficient because C<PL_na> must
+be accessed in thread-local storage in threaded Perl. In any case, remember
+that Perl allows arbitrary strings of data that may both contain NULs and
+might not be terminated by a NUL.
+
+Also remember that C doesn't allow you to safely say C<foo(SvPV(s, len),
+len);>. It might work with your compiler, but it won't work for everyone.
+Break this sort of statement up into separate assignments:
+
+ STRLEN len;
+ char * ptr;
+ ptr = SvPV(len);
+ foo(ptr, len);
If you want to know if the scalar value is TRUE, you can use:
If you want to append something to the end of string stored in an C<SV*>,
you can use the following functions:
- void sv_catpv(SV*, char*);
- void sv_catpvn(SV*, char*, int);
+ void sv_catpv(SV*, const char*);
+ void sv_catpvn(SV*, const char*, STRLEN);
+ void sv_catpvf(SV*, const char*, ...);
+ void sv_catpvfn(SV*, const char*, STRLEN, va_list *, SV **, I32, bool);
void sv_catsv(SV*, SV*);
The first function calculates the length of the string to be appended by
using C<strlen>. In the second, you specify the length of the string
-yourself. The third function extends the string stored in the first SV
-with the string stored in the second SV. It also forces the second SV to
-be interpreted as a string.
+yourself. The third function processes its arguments like C<sprintf> and
+appends the formatted output. The fourth function works like C<vsprintf>.
+You can specify the address and length of an array of SVs instead of the
+va_list argument. The fifth function extends the string stored in the first
+SV with the string stored in the second SV. It also forces the second SV
+to be interpreted as a string.
+
+The C<sv_cat*()> functions are not generic enough to operate on values that
+have "magic". See L<Magic Virtual Tables> later in this document.
If you know the name of a scalar variable, you can get a pointer to its SV
by using the following:
SvOK(SV*)
-The scalar C<undef> value is stored in an SV instance called C<sv_undef>. Its
+The scalar C<undef> value is stored in an SV instance called C<PL_sv_undef>. Its
address can be used whenever an C<SV*> is needed.
-There are also the two values C<sv_yes> and C<sv_no>, which contain Boolean
-TRUE and FALSE values, respectively. Like C<sv_undef>, their addresses can
+There are also the two values C<PL_sv_yes> and C<PL_sv_no>, which contain Boolean
+TRUE and FALSE values, respectively. Like C<PL_sv_undef>, their addresses can
be used whenever an C<SV*> is needed.
-Do not be fooled into thinking that C<(SV *) 0> is the same as C<&sv_undef>.
+Do not be fooled into thinking that C<(SV *) 0> is the same as C<&PL_sv_undef>.
Take this code:
SV* sv = (SV*) 0;
sv_setsv(ST(0), sv);
This code tries to return a new SV (which contains the value 42) if it should
-return a real value, or undef otherwise. Instead it has returned a null
+return a real value, or undef otherwise. Instead it has returned a NULL
pointer which, somewhere down the line, will cause a segmentation violation,
-bus error, or just weird results. Change the zero to C<&sv_undef> in the first
+bus error, or just weird results. Change the zero to C<&PL_sv_undef> in the first
line and all will be well.
To free an SV that you've created, call C<SvREFCNT_dec(SV*)>. Normally this
like $#array in Perl). If the array is empty, -1 is returned. The
C<av_fetch> function returns the value at index C<key>, but if C<lval>
is non-zero, then C<av_fetch> will store an undef value at that index.
-The C<av_store> function stores the value C<val> at index C<key>.
-note that C<av_fetch> and C<av_store> both return C<SV**>'s, not C<SV*>'s
-as their return value.
+The C<av_store> function stores the value C<val> at index C<key>, and does
+not increment the reference count of C<val>. Thus the caller is responsible
+for taking care of that, and if C<av_store> returns NULL, the caller will
+have to decrement the reference count to avoid a memory leak. Note that
+C<av_fetch> and C<av_store> both return C<SV**>'s, not C<SV*>'s as their
+return value.
void av_clear(AV*);
void av_undef(AV*);
The C<av_clear> function deletes all the elements in the AV* array, but
does not actually delete the array itself. The C<av_undef> function will
delete all the elements in the array plus the array itself. The
-C<av_extend> function extends the array so that it contains C<key>
-elements. If C<key> is less than the current length of the array, then
-nothing is done.
+C<av_extend> function extends the array so that it contains at least C<key+1>
+elements. If C<key+1> is less than the currently allocated length of the array,
+then nothing is done.
If you know the name of an array variable, you can get a pointer to its AV
by using the following:
This returns NULL if the variable does not exist.
+See L<Understanding the Magic of Tied Hashes and Arrays> for more
+information on how to use the array access functions on tied arrays.
+
=head2 Working with HVs
To create an HV, you use the following routine:
Once the HV has been created, the following operations are possible on HVs:
- SV** hv_store(HV*, char* key, U32 klen, SV* val, U32 hash);
- SV** hv_fetch(HV*, char* key, U32 klen, I32 lval);
+ SV** hv_store(HV*, const char* key, U32 klen, SV* val, U32 hash);
+ SV** hv_fetch(HV*, const char* key, U32 klen, I32 lval);
The C<klen> parameter is the length of the key being passed in (Note that
you cannot pass 0 in as a value of C<klen> to tell Perl to measure the
These two functions check if a hash table entry exists, and deletes it.
- bool hv_exists(HV*, char* key, U32 klen);
- SV* hv_delete(HV*, char* key, U32 klen, I32 flags);
+ bool hv_exists(HV*, const char* key, U32 klen);
+ SV* hv_delete(HV*, const char* key, U32 klen, I32 flags);
If C<flags> does not include the C<G_DISCARD> flag then C<hv_delete> will
create and return a mortal copy of the deleted value.
The hash algorithm is defined in the C<PERL_HASH(hash, key, klen)> macro:
- i = klen;
hash = 0;
- s = key;
- while (i--)
- hash = hash * 33 + *s++;
+ while (klen--)
+ hash = (hash * 33) + *key++;
+ hash = hash + (hash >> 5); /* after 5.006 */
+
+The last step was added in version 5.006 to improve distribution of
+lower bits in the resulting hash value.
+
+See L<Understanding the Magic of Tied Hashes and Arrays> for more
+information on how to use the hash access functions on tied hashes.
=head2 Hash API Extensions
HeKEY(HE* he)
HeKLEN(HE* he)
+Note that both C<hv_store> and C<hv_store_ent> do not increment the
+reference count of the stored C<val>, which is the caller's responsibility.
+If these functions return a NULL value, the caller will usually have to
+decrement the reference count of C<val> to avoid a memory leak.
=head2 References
point to. If C<classname> is non-null, the SV is blessed into the specified
class. SV is returned.
- SV* newSVrv(SV* rv, char* classname);
+ SV* newSVrv(SV* rv, const char* classname);
Copies integer or double into an SV whose reference is C<rv>. SV is blessed
if C<classname> is non-null.
- SV* sv_setref_iv(SV* rv, char* classname, IV iv);
- SV* sv_setref_nv(SV* rv, char* classname, NV iv);
+ SV* sv_setref_iv(SV* rv, const char* classname, IV iv);
+ SV* sv_setref_nv(SV* rv, const char* classname, NV iv);
Copies the pointer value (I<the address, not the string!>) into an SV whose
reference is rv. SV is blessed if C<classname> is non-null.
- SV* sv_setref_pv(SV* rv, char* classname, PV iv);
+ SV* sv_setref_pv(SV* rv, const char* classname, PV iv);
Copies string into an SV whose reference is C<rv>. Set length to 0 to let
Perl calculate the string length. SV is blessed if C<classname> is non-null.
- SV* sv_setref_pvn(SV* rv, char* classname, PV iv, int length);
+ SV* sv_setref_pvn(SV* rv, const char* classname, PV iv, STRLEN length);
+
+Tests whether the SV is blessed into the specified class. It does not
+check inheritance relationships.
+
+ int sv_isa(SV* sv, const char* name);
+
+Tests whether the SV is a reference to a blessed object.
+
+ int sv_isobject(SV* sv);
+
+Tests whether the SV is derived from the specified class. SV can be either
+a reference to a blessed object or a string containing a class name. This
+is the function implementing the C<UNIVERSAL::isa> functionality.
+
+ bool sv_derived_from(SV* sv, const char* name);
- int sv_isa(SV* sv, char* name);
- int sv_isobject(SV* sv);
+To check if you've got an object derived from a specific class you have
+to write:
+
+ if (sv_isobject(sv) && sv_derived_from(sv, class)) { ... }
=head2 Creating New Variables
Scalar Value
Array Value
Hash Value
- File Handle
- Directory Handle
+ I/O Handle
Format
Subroutine
-There is a single stash called "defstash" that holds the items that exist
+There is a single stash called "PL_defstash" that holds the items that exist
in the "main" package. To get at the items in other packages, append the
string "::" to the package name. The items in the "Foo" package are in
-the stash "Foo::" in defstash. The items in the "Bar::Baz" package are
+the stash "Foo::" in PL_defstash. The items in the "Bar::Baz" package are
in the stash "Baz::" in "Bar::"'s stash.
To get the stash pointer for a particular package, use the function:
- HV* gv_stashpv(char* name, I32 create)
+ HV* gv_stashpv(const char* name, I32 create)
HV* gv_stashsv(SV*, I32 create)
The first function takes a literal string, the second uses the string stored
Perl adds magic to an SV using the sv_magic function:
- void sv_magic(SV* sv, SV* obj, int how, char* name, I32 namlen);
+ void sv_magic(SV* sv, SV* obj, int how, const char* name, I32 namlen);
The C<sv> argument is a pointer to the SV that is to acquire a new magical
feature.
The C<obj> argument is stored in the C<mg_obj> field of the C<MAGIC>
structure. If it is not the same as the C<sv> argument, the reference
count of the C<obj> object is incremented. If it is the same, or if
-the C<how> argument is "#", or if it is a null pointer, then C<obj> is
+the C<how> argument is "#", or if it is a NULL pointer, then C<obj> is
merely stored, without the reference count being incremented.
There is also a function to add magic to an C<HV>:
The current kinds of Magic Virtual Tables are:
- mg_type MGVTBL Type of magical
+ mg_type MGVTBL Type of magic
------- ------ ----------------------------
- \0 vtbl_sv Regexp???
- A vtbl_amagic Operator Overloading
- a vtbl_amagicelem Operator Overloading
- c 0 Used in Operator Overloading
- B vtbl_bm Boyer-Moore???
+ \0 vtbl_sv Special scalar variable
+ A vtbl_amagic %OVERLOAD hash
+ a vtbl_amagicelem %OVERLOAD hash element
+ c (none) Holds overload table (AMT) on stash
+ B vtbl_bm Boyer-Moore (fast string search)
E vtbl_env %ENV hash
e vtbl_envelem %ENV hash element
- g vtbl_mglob Regexp /g flag???
+ f vtbl_fm Formline ('compiled' format)
+ g vtbl_mglob m//g target / study()ed string
I vtbl_isa @ISA array
i vtbl_isaelem @ISA array element
- L 0 (but sets RMAGICAL) Perl Module/Debugger???
- l vtbl_dbline Debugger?
+ k vtbl_nkeys scalar(keys()) lvalue
+ L (none) Debugger %_<filename
+ l vtbl_dbline Debugger %_<filename element
o vtbl_collxfrm Locale transformation
- P vtbl_pack Tied Array or Hash
- p vtbl_packelem Tied Array or Hash element
- q vtbl_packelem Tied Scalar or Handle
- S vtbl_sig Signal Hash
- s vtbl_sigelem Signal Hash element
+ P vtbl_pack Tied array or hash
+ p vtbl_packelem Tied array or hash element
+ q vtbl_packelem Tied scalar or handle
+ S vtbl_sig %SIG hash
+ s vtbl_sigelem %SIG hash element
t vtbl_taint Taintedness
- U vtbl_uvar ???
- v vtbl_vec Vector
- x vtbl_substr Substring???
- y vtbl_itervar Shadow "foreach" iterator variable
- * vtbl_glob GV???
- # vtbl_arylen Array Length
- . vtbl_pos $. scalar variable
- ~ None Used by certain extensions
+ U vtbl_uvar Available for use by extensions
+ v vtbl_vec vec() lvalue
+ x vtbl_substr substr() lvalue
+ y vtbl_defelem Shadow "foreach" iterator variable /
+ smart parameter vivification
+ * vtbl_glob GV (typeglob)
+ # vtbl_arylen Array length ($#ary)
+ . vtbl_pos pos() lvalue
+ ~ (none) Available for use by extensions
When an uppercase and lowercase letter both exist in the table, then the
uppercase letter is used to represent some kind of composite type (a list
or a hash), and the lowercase letter is used to represent an element of
that composite type.
-The '~' magic type is defined specifically for use by extensions and
-will not be used by perl itself. Extensions can use ~ magic to 'attach'
-private information to variables (typically objects). This is especially
-useful because there is no way for normal perl code to corrupt this
-private information (unlike using extra elements of a hash object).
+The '~' and 'U' magic types are defined specifically for use by
+extensions and will not be used by perl itself. Extensions can use
+'~' magic to 'attach' private information to variables (typically
+objects). This is especially useful because there is no way for
+normal perl code to corrupt this private information (unlike using
+extra elements of a hash object).
+
+Similarly, 'U' magic can be used much like tie() to call a C function
+any time a scalar's value is used or changed. The C<MAGIC>'s
+C<mg_ptr> field points to a C<ufuncs> structure:
+
+ struct ufuncs {
+ I32 (*uf_val)(IV, SV*);
+ I32 (*uf_set)(IV, SV*);
+ IV uf_index;
+ };
-Note that because multiple extensions may be using ~ magic it is
-important for extensions to take extra care with it. Typically only
-using it on objects blessed into the same class as the extension
-is sufficient. It may also be appropriate to add an I32 'signature'
-at the top of the private data area and check that.
+When the SV is read from or written to, the C<uf_val> or C<uf_set>
+function will be called with C<uf_index> as the first arg and a
+pointer to the SV as the second. A simple example of how to add 'U'
+magic is shown below. Note that the ufuncs structure is copied by
+sv_magic, so you can safely allocate it on the stack.
+
+ void
+ Umagic(sv)
+ SV *sv;
+ PREINIT:
+ struct ufuncs uf;
+ CODE:
+ uf.uf_val = &my_get_fn;
+ uf.uf_set = &my_set_fn;
+ uf.uf_index = 0;
+ sv_magic(sv, 0, 'U', (char*)&uf, sizeof(uf));
+
+Note that because multiple extensions may be using '~' or 'U' magic,
+it is important for extensions to take extra care to avoid conflict.
+Typically only using the magic on objects blessed into the same class
+as the extension is sufficient. For '~' magic, it may also be
+appropriate to add an I32 'signature' at the top of the private data
+area and check that.
+
+Also note that the C<sv_set*()> and C<sv_cat*()> functions described
+earlier do B<not> invoke 'set' magic on their targets. This must
+be done by the user either by calling the C<SvSETMAGIC()> macro after
+calling these functions, or by using one of the C<sv_set*_mg()> or
+C<sv_cat*_mg()> functions. Similarly, generic C code must call the
+C<SvGETMAGIC()> macro to invoke any 'get' magic if they use an SV
+obtained from external sources in functions that don't handle magic.
+L<API LISTING> later in this document identifies such functions.
+For example, calls to the C<sv_cat*()> functions typically need to be
+followed by C<SvSETMAGIC()>, but they don't need a prior C<SvGETMAGIC()>
+since their implementation handles 'get' magic.
=head2 Finding Magic
If the SV does not have that magical feature, C<NULL> is returned. Also,
if the SV is not of type SVt_PVMG, Perl may core dump.
- int mg_copy(SV* sv, SV* nsv, char* key, STRLEN klen);
+ int mg_copy(SV* sv, SV* nsv, const char* key, STRLEN klen);
This routine checks to see what types of magic C<sv> has. If the mg_type
field is an uppercase letter, then the mg_obj is copied to C<nsv>, but
the mg_type field is changed to be the lowercase letter.
+=head2 Understanding the Magic of Tied Hashes and Arrays
+
+Tied hashes and arrays are magical beasts of the 'P' magic type.
+
+WARNING: As of the 5.004 release, proper usage of the array and hash
+access functions requires understanding a few caveats. Some
+of these caveats are actually considered bugs in the API, to be fixed
+in later releases, and are bracketed with [MAYCHANGE] below. If
+you find yourself actually applying such information in this section, be
+aware that the behavior may change in the future, umm, without warning.
+
+The perl tie function associates a variable with an object that implements
+the various GET, SET etc methods. To perform the equivalent of the perl
+tie function from an XSUB, you must mimic this behaviour. The code below
+carries out the necessary steps - firstly it creates a new hash, and then
+creates a second hash which it blesses into the class which will implement
+the tie methods. Lastly it ties the two hashes together, and returns a
+reference to the new tied hash. Note that the code below does NOT call the
+TIEHASH method in the MyTie class -
+see L<Calling Perl Routines from within C Programs> for details on how
+to do this.
+
+ SV*
+ mytie()
+ PREINIT:
+ HV *hash;
+ HV *stash;
+ SV *tie;
+ CODE:
+ hash = newHV();
+ tie = newRV_noinc((SV*)newHV());
+ stash = gv_stashpv("MyTie", TRUE);
+ sv_bless(tie, stash);
+ hv_magic(hash, tie, 'P');
+ RETVAL = newRV_noinc(hash);
+ OUTPUT:
+ RETVAL
+
+The C<av_store> function, when given a tied array argument, merely
+copies the magic of the array onto the value to be "stored", using
+C<mg_copy>. It may also return NULL, indicating that the value did not
+actually need to be stored in the array. [MAYCHANGE] After a call to
+C<av_store> on a tied array, the caller will usually need to call
+C<mg_set(val)> to actually invoke the perl level "STORE" method on the
+TIEARRAY object. If C<av_store> did return NULL, a call to
+C<SvREFCNT_dec(val)> will also be usually necessary to avoid a memory
+leak. [/MAYCHANGE]
+
+The previous paragraph is applicable verbatim to tied hash access using the
+C<hv_store> and C<hv_store_ent> functions as well.
+
+C<av_fetch> and the corresponding hash functions C<hv_fetch> and
+C<hv_fetch_ent> actually return an undefined mortal value whose magic
+has been initialized using C<mg_copy>. Note the value so returned does not
+need to be deallocated, as it is already mortal. [MAYCHANGE] But you will
+need to call C<mg_get()> on the returned value in order to actually invoke
+the perl level "FETCH" method on the underlying TIE object. Similarly,
+you may also call C<mg_set()> on the return value after possibly assigning
+a suitable value to it using C<sv_setsv>, which will invoke the "STORE"
+method on the TIE object. [/MAYCHANGE]
+
+[MAYCHANGE]
+In other words, the array or hash fetch/store functions don't really
+fetch and store actual values in the case of tied arrays and hashes. They
+merely call C<mg_copy> to attach magic to the values that were meant to be
+"stored" or "fetched". Later calls to C<mg_get> and C<mg_set> actually
+do the job of invoking the TIE methods on the underlying objects. Thus
+the magic mechanism currently implements a kind of lazy access to arrays
+and hashes.
+
+Currently (as of perl version 5.004), use of the hash and array access
+functions requires the user to be aware of whether they are operating on
+"normal" hashes and arrays, or on their tied variants. The API may be
+changed to provide more transparent access to both tied and normal data
+types in future versions.
+[/MAYCHANGE]
+
+You would do well to understand that the TIEARRAY and TIEHASH interfaces
+are mere sugar to invoke some perl method calls while using the uniform hash
+and array syntax. The use of this sugar imposes some overhead (typically
+about two to four extra opcodes per FETCH/STORE operation, in addition to
+the creation of all the mortal variables required to invoke the methods).
+This overhead will be comparatively small if the TIE methods are themselves
+substantial, but if they are only a few statements long, the overhead
+will not be insignificant.
+
+=head2 Localizing changes
+
+Perl has a very handy construction
+
+ {
+ local $var = 2;
+ ...
+ }
+
+This construction is I<approximately> equivalent to
+
+ {
+ my $oldvar = $var;
+ $var = 2;
+ ...
+ $var = $oldvar;
+ }
+
+The biggest difference is that the first construction would
+reinstate the initial value of $var, irrespective of how control exits
+the block: C<goto>, C<return>, C<die>/C<eval> etc. It is a little bit
+more efficient as well.
+
+There is a way to achieve a similar task from C via Perl API: create a
+I<pseudo-block>, and arrange for some changes to be automatically
+undone at the end of it, either explicit, or via a non-local exit (via
+die()). A I<block>-like construct is created by a pair of
+C<ENTER>/C<LEAVE> macros (see L<perlcall/"Returning a Scalar">).
+Such a construct may be created specially for some important localized
+task, or an existing one (like boundaries of enclosing Perl
+subroutine/block, or an existing pair for freeing TMPs) may be
+used. (In the second case the overhead of additional localization must
+be almost negligible.) Note that any XSUB is automatically enclosed in
+an C<ENTER>/C<LEAVE> pair.
+
+Inside such a I<pseudo-block> the following service is available:
+
+=over
+
+=item C<SAVEINT(int i)>
+
+=item C<SAVEIV(IV i)>
+
+=item C<SAVEI32(I32 i)>
+
+=item C<SAVELONG(long i)>
+
+These macros arrange things to restore the value of integer variable
+C<i> at the end of enclosing I<pseudo-block>.
+
+=item C<SAVESPTR(s)>
+
+=item C<SAVEPPTR(p)>
+
+These macros arrange things to restore the value of pointers C<s> and
+C<p>. C<s> must be a pointer of a type which survives conversion to
+C<SV*> and back, C<p> should be able to survive conversion to C<char*>
+and back.
+
+=item C<SAVEFREESV(SV *sv)>
+
+The refcount of C<sv> would be decremented at the end of
+I<pseudo-block>. This is similar to C<sv_2mortal>, which should (?) be
+used instead.
+
+=item C<SAVEFREEOP(OP *op)>
+
+The C<OP *> is op_free()ed at the end of I<pseudo-block>.
+
+=item C<SAVEFREEPV(p)>
+
+The chunk of memory which is pointed to by C<p> is Safefree()ed at the
+end of I<pseudo-block>.
+
+=item C<SAVECLEARSV(SV *sv)>
+
+Clears a slot in the current scratchpad which corresponds to C<sv> at
+the end of I<pseudo-block>.
+
+=item C<SAVEDELETE(HV *hv, char *key, I32 length)>
+
+The key C<key> of C<hv> is deleted at the end of I<pseudo-block>. The
+string pointed to by C<key> is Safefree()ed. If one has a I<key> in
+short-lived storage, the corresponding string may be reallocated like
+this:
+
+ SAVEDELETE(PL_defstash, savepv(tmpbuf), strlen(tmpbuf));
+
+=item C<SAVEDESTRUCTOR(f,p)>
+
+At the end of I<pseudo-block> the function C<f> is called with the
+only argument (of type C<void*>) C<p>.
+
+=item C<SAVESTACK_POS()>
+
+The current offset on the Perl internal stack (cf. C<SP>) is restored
+at the end of I<pseudo-block>.
+
+=back
+
+The following API list contains functions, thus one needs to
+provide pointers to the modifiable data explicitly (either C pointers,
+or Perlish C<GV *>s). Where the above macros take C<int>, a similar
+function takes C<int *>.
+
+=over
+
+=item C<SV* save_scalar(GV *gv)>
+
+Equivalent to Perl code C<local $gv>.
+
+=item C<AV* save_ary(GV *gv)>
+
+=item C<HV* save_hash(GV *gv)>
+
+Similar to C<save_scalar>, but localize C<@gv> and C<%gv>.
+
+=item C<void save_item(SV *item)>
+
+Duplicates the current value of C<SV>, on the exit from the current
+C<ENTER>/C<LEAVE> I<pseudo-block> will restore the value of C<SV>
+using the stored value.
+
+=item C<void save_list(SV **sarg, I32 maxsarg)>
+
+A variant of C<save_item> which takes multiple arguments via an array
+C<sarg> of C<SV*> of length C<maxsarg>.
+
+=item C<SV* save_svref(SV **sptr)>
+
+Similar to C<save_scalar>, but will reinstate a C<SV *>.
+
+=item C<void save_aptr(AV **aptr)>
+
+=item C<void save_hptr(HV **hptr)>
+
+Similar to C<save_svref>, but localize C<AV *> and C<HV *>.
+
+=back
+
+The C<Alias> module implements localization of the basic types within the
+I<caller's scope>. People who are interested in how to localize things in
+the containing scope should take a look there too.
+
=head1 Subroutines
=head2 XSUBs and the Argument Stack
To handle this situation, the PPCODE directive is used and the stack is
extended using the macro:
- EXTEND(sp, num);
+ EXTEND(SP, num);
-where C<sp> is the stack pointer, and C<num> is the number of elements the
-stack should be extended by.
+where C<SP> is the macro that represents the local copy of the stack pointer,
+and C<num> is the number of elements the stack should be extended by.
Now that there is room on the stack, values can be pushed on it using the
macros to push IVs, doubles, strings, and SV pointers respectively:
within a C program. These four are:
I32 perl_call_sv(SV*, I32);
- I32 perl_call_pv(char*, I32);
- I32 perl_call_method(char*, I32);
- I32 perl_call_argv(char*, I32, register char**);
+ I32 perl_call_pv(const char*, I32);
+ I32 perl_call_method(const char*, I32);
+ I32 perl_call_argv(const char*, I32, register char**);
The routine most often used is C<perl_call_sv>. The C<SV*> argument
contains either the name of the Perl subroutine to be called, or a
functions:
dSP
+ SP
PUSHMARK()
PUTBACK
SPAGAIN
=head2 Memory Allocation
-It is suggested that you use the version of malloc that is distributed
+All memory meant to be used with the Perl API functions should be manipulated
+using the macros described in this section. The macros provide the necessary
+transparency between differences in the actual malloc implementation that is
+used within perl.
+
+It is suggested that you enable the version of malloc that is distributed
with Perl. It keeps pools of various sizes of unallocated memory in
order to satisfy allocation requests more quickly. However, on some
platforms, it may cause spurious malloc or free errors.
/ \
$b $c
-(but slightly more complicated). This tree reflect the way Perl
+(but slightly more complicated). This tree reflects the way Perl
parsed your code, but has nothing to do with the execution order.
There is an additional "thread" going through the nodes of the tree
which shows the order of execution of the nodes. In our simplified
forget to run C<make regen_headers> if you modify this file).
A check routine is called when the node is fully constructed except
-for the execution-order thread. Since at this time there is no
+for the execution-order thread. Since at this time there are no
back-links to the currently constructed node, one can do most any
operation to the top-level node, including freeing it and/or creating
new nodes above/below it.
=head2 Compile pass 2: context propagation
When a context for a part of compile tree is known, it is propagated
-down through the tree. Aat this time the context can have 5 values
+down through the tree. At this time the context can have 5 values
(instead of 2 for runtime context): void, boolean, scalar, list, and
lvalue. In contrast with the pass 1 this pass is processed from top
to bottom: a node's context determines the context for its children.
After the compile tree for a subroutine (or for an C<eval> or a file)
is created, an additional pass over the code is performed. This pass
is neither top-down or bottom-up, but in the execution order (with
-additional compilications for conditionals). These optimizations are
+additional complications for conditionals). These optimizations are
done in the subroutine peep(). Optimizations performed at this stage
are subject to the same restrictions as in the pass 2.
useful to extension writers or that may be found while reading other
extensions.
-=over 8
+Note that all Perl API global variables must be referenced with the C<PL_>
+prefix. Some macros are provided for compatibility with the older,
+unadorned names, but this support will be removed in a future release.
-=item AvFILL
+It is strongly recommended that all Perl API functions that don't begin
+with C<perl> be referenced with an explicit C<Perl_> prefix.
-See C<av_len>.
+The sort order of the listing is case insensitive, with any
+occurrences of '_' ignored for the purpose of sorting.
+
+=over 8
=item av_clear
-Clears an array, making it empty.
+Clears an array, making it empty. Does not free the memory used by the
+array itself.
- void av_clear _((AV* ar));
+ void av_clear (AV* ar)
=item av_extend
Pre-extend an array. The C<key> is the index to which the array should be
extended.
- void av_extend _((AV* ar, I32 key));
+ void av_extend (AV* ar, I32 key)
=item av_fetch
index. If C<lval> is set then the fetch will be part of a store. Check
that the return value is non-null before dereferencing it to a C<SV*>.
- SV** av_fetch _((AV* ar, I32 key, I32 lval));
+See L<Understanding the Magic of Tied Hashes and Arrays> for more
+information on how to use this function on tied arrays.
+
+ SV** av_fetch (AV* ar, I32 key, I32 lval)
+
+=item AvFILL
+
+Same as C<av_len()>. Deprecated, use C<av_len()> instead.
=item av_len
Returns the highest index in the array. Returns -1 if the array is empty.
- I32 av_len _((AV* ar));
+ I32 av_len (AV* ar)
=item av_make
into the array, so they may be freed after the call to av_make. The new AV
will have a reference count of 1.
- AV* av_make _((I32 size, SV** svp));
+ AV* av_make (I32 size, SV** svp)
=item av_pop
-Pops an SV off the end of the array. Returns C<&sv_undef> if the array is
+Pops an SV off the end of the array. Returns C<&PL_sv_undef> if the array is
empty.
- SV* av_pop _((AV* ar));
+ SV* av_pop (AV* ar)
=item av_push
Pushes an SV onto the end of the array. The array will grow automatically
to accommodate the addition.
- void av_push _((AV* ar, SV* val));
+ void av_push (AV* ar, SV* val)
=item av_shift
Shifts an SV off the beginning of the array.
- SV* av_shift _((AV* ar));
+ SV* av_shift (AV* ar)
=item av_store
Stores an SV in an array. The array index is specified as C<key>. The
-return value will be null if the operation failed, otherwise it can be
-dereferenced to get the original C<SV*>.
+return value will be NULL if the operation failed or if the value did not
+need to be actually stored within the array (as in the case of tied arrays).
+Otherwise it can be dereferenced to get the original C<SV*>. Note that the
+caller is responsible for suitably incrementing the reference count of C<val>
+before the call, and decrementing it if the function returned NULL.
- SV** av_store _((AV* ar, I32 key, SV* val));
+See L<Understanding the Magic of Tied Hashes and Arrays> for more
+information on how to use this function on tied arrays.
+
+ SV** av_store (AV* ar, I32 key, SV* val)
=item av_undef
-Undefines the array.
+Undefines the array. Frees the memory used by the array itself.
- void av_undef _((AV* ar));
+ void av_undef (AV* ar)
=item av_unshift
-Unshift an SV onto the beginning of the array. The array will grow
-automatically to accommodate the addition.
+Unshift the given number of C<undef> values onto the beginning of the
+array. The array will grow automatically to accommodate the addition.
+You must then use C<av_store> to assign values to these new elements.
- void av_unshift _((AV* ar, I32 num));
+ void av_unshift (AV* ar, I32 num)
=item CLASS
The XSUB-writer's interface to the C C<memcpy> function. The C<s> is the
source, C<d> is the destination, C<n> is the number of items, and C<t> is
-the type.
+the type. May fail on overlapping copies. See also C<Move>.
- (void) Copy( s, d, n, t );
+ void Copy( s, d, n, t )
=item croak
Returns the stash of the CV.
- HV * CvSTASH( SV* sv )
+ HV* CvSTASH( SV* sv )
-=item DBsingle
+=item PL_DBsingle
When Perl is run in debugging mode, with the B<-d> switch, this SV is a
boolean which indicates whether subs are being single-stepped.
Single-stepping is automatically turned on after every step. This is the C
-variable which corresponds to Perl's $DB::single variable. See C<DBsub>.
+variable which corresponds to Perl's $DB::single variable. See C<PL_DBsub>.
-=item DBsub
+=item PL_DBsub
When Perl is run in debugging mode, with the B<-d> switch, this GV contains
the SV which holds the name of the sub being debugged. This is the C
-variable which corresponds to Perl's $DB::sub variable. See C<DBsingle>.
+variable which corresponds to Perl's $DB::sub variable. See C<PL_DBsingle>.
The sub name can be found by
- SvPV( GvSV( DBsub ), na )
+ SvPV( GvSV( PL_DBsub ), len )
-=item DBtrace
+=item PL_DBtrace
Trace variable used when Perl is run in debugging mode, with the B<-d>
switch. This is the C variable which corresponds to Perl's $DB::trace
-variable. See C<DBsingle>.
+variable. See C<PL_DBsingle>.
=item dMARK
Saves the original stack mark for the XSUB. See C<ORIGMARK>.
-=item dowarn
+=item PL_dowarn
The C variable which corresponds to Perl's $^W warning variable.
=item dSP
-Declares a stack pointer variable, C<sp>, for the XSUB. See C<SP>.
+Declares a local copy of perl's stack pointer for the XSUB, available via
+the C<SP> macro. See C<SP>.
=item dXSARGS
Sets up the C<ix> variable for an XSUB which has aliases. This is usually
handled automatically by C<xsubpp>.
-=item dXSI32
+=item do_binmode
-Sets up the C<ix> variable for an XSUB which has aliases. This is usually
-handled automatically by C<xsubpp>.
+Switches filehandle to binmode. C<iotype> is what C<IoTYPE(io)> would
+contain.
+
+ do_binmode(fp, iotype, TRUE);
=item ENTER
Used to extend the argument stack for an XSUB's return values.
- EXTEND( sp, int x );
+ EXTEND( sp, int x )
+
+=item fbm_compile
+
+Analyses the string in order to make fast searches on it using fbm_instr() --
+the Boyer-Moore algorithm.
+
+ void fbm_compile(SV* sv, U32 flags)
+
+=item fbm_instr
+
+Returns the location of the SV in the string delimited by C<str> and
+C<strend>. It returns C<Nullch> if the string can't be found. The
+C<sv> does not have to be fbm_compiled, but the search will not be as
+fast then.
+
+ char* fbm_instr(char *str, char *strend, SV *sv, U32 flags)
=item FREETMPS
Used to indicate scalar context. See C<GIMME_V>, C<GIMME>, and L<perlcall>.
-=item G_VOID
-
-Used to indicate void context. See C<GIMME_V> and L<perlcall>.
-
=item gv_fetchmeth
Returns the glob with the given C<name> and a defined subroutine or
C<NULL>. The glob lives in the given C<stash>, or in the stashes
-accessable via @ISA and @<UNIVERSAL>.
+accessible via @ISA and @UNIVERSAL.
The argument C<level> should be either 0 or -1. If C<level==0>, as a
side-effect creates a glob with the given C<name> in the given
you should not use the GV directly; instead, you should use the
method's CV, which can be obtained from the GV with the C<GvCV> macro.
- GV* gv_fetchmeth _((HV* stash, char* name, STRLEN len, I32 level));
+ GV* gv_fetchmeth (HV* stash, const char* name, STRLEN len, I32 level)
=item gv_fetchmethod
=item gv_fetchmethod_autoload
Returns the glob which contains the subroutine to call to invoke the
-method on the C<stash>. In fact in the presense of autoloading this may
+method on the C<stash>. In fact in the presence of autoloading this may
be the glob for "AUTOLOAD". In this case the corresponding variable
$AUTOLOAD is already setup.
The warning against passing the GV returned by C<gv_fetchmeth> to
C<perl_call_sv> apply equally to these functions.
- GV* gv_fetchmethod _((HV* stash, char* name));
- GV* gv_fetchmethod_autoload _((HV* stash, char* name,
- I32 autoload));
+ GV* gv_fetchmethod (HV* stash, const char* name)
+ GV* gv_fetchmethod_autoload (HV* stash, const char* name, I32 autoload)
+
+=item G_VOID
+
+Used to indicate void context. See C<GIMME_V> and L<perlcall>.
=item gv_stashpv
then the package will be created if it does not already exist. If C<create>
is not set and the package does not exist then NULL is returned.
- HV* gv_stashpv _((char* name, I32 create));
+ HV* gv_stashpv (const char* name, I32 create)
=item gv_stashsv
Returns a pointer to the stash for a specified package. See C<gv_stashpv>.
- HV* gv_stashsv _((SV* sv, I32 create));
+ HV* gv_stashsv (SV* sv, I32 create)
=item GvSV
=item HeHASH
-Returns the computed hash (type C<U32>) stored in the hash entry.
+Returns the computed hash stored in the hash entry.
- HeHASH(HE* he)
+ U32 HeHASH(HE* he)
=item HeKEY
C<HeKLEN()>. Can be assigned to. The C<HePV()> or C<HeSVKEY()> macros
are usually preferable for finding the value of a key.
- HeKEY(HE* he)
+ char* HeKEY(HE* he)
=item HeKLEN
Can be assigned to. The C<HePV()> macro is usually preferable for finding
key lengths.
- HeKLEN(HE* he)
+ int HeKLEN(HE* he)
=item HePV
necessary dereferencing of possibly C<SV*> keys. The length of
the string is placed in C<len> (this is a macro, so do I<not> use
C<&len>). If you do not care about what the length of the key is,
-you may use the global variable C<na>. Remember though, that hash
+you may use the global variable C<PL_na>, though this is rather less
+efficient than using a local variable. Remember though, that hash
keys in perl are free to contain embedded nulls, so using C<strlen()>
or similar is not a good way to find the length of hash keys.
This is very similar to the C<SvPV()> macro described elsewhere in
this document.
- HePV(HE* he, STRLEN len)
+ char* HePV(HE* he, STRLEN len)
=item HeSVKEY
Clears a hash, making it empty.
- void hv_clear _((HV* tb));
-
-=item hv_delayfree_ent
-
-Releases a hash entry, such as while iterating though the hash, but
-delays actual freeing of key and value until the end of the current
-statement (or thereabouts) with C<sv_2mortal>. See C<hv_iternext>
-and C<hv_free_ent>.
-
- void hv_delayfree_ent _((HV* hv, HE* entry));
+ void hv_clear (HV* tb)
=item hv_delete
Deletes a key/value pair in the hash. The value SV is removed from the hash
and returned to the caller. The C<klen> is the length of the key. The
-C<flags> value will normally be zero; if set to G_DISCARD then null will be
+C<flags> value will normally be zero; if set to G_DISCARD then NULL will be
returned.
- SV* hv_delete _((HV* tb, char* key, U32 klen, I32 flags));
+ SV* hv_delete (HV* tb, const char* key, U32 klen, I32 flags)
=item hv_delete_ent
Deletes a key/value pair in the hash. The value SV is removed from the hash
and returned to the caller. The C<flags> value will normally be zero; if set
-to G_DISCARD then null will be returned. C<hash> can be a valid precomputed
+to G_DISCARD then NULL will be returned. C<hash> can be a valid precomputed
hash value, or 0 to ask for it to be computed.
- SV* hv_delete_ent _((HV* tb, SV* key, I32 flags, U32 hash));
+ SV* hv_delete_ent (HV* tb, SV* key, I32 flags, U32 hash)
=item hv_exists
Returns a boolean indicating whether the specified hash key exists. The
C<klen> is the length of the key.
- bool hv_exists _((HV* tb, char* key, U32 klen));
+ bool hv_exists (HV* tb, const char* key, U32 klen)
=item hv_exists_ent
Returns a boolean indicating whether the specified hash key exists. C<hash>
can be a valid precomputed hash value, or 0 to ask for it to be computed.
- bool hv_exists_ent _((HV* tb, SV* key, U32 hash));
+ bool hv_exists_ent (HV* tb, SV* key, U32 hash)
=item hv_fetch
part of a store. Check that the return value is non-null before
dereferencing it to a C<SV*>.
- SV** hv_fetch _((HV* tb, char* key, U32 klen, I32 lval));
+See L<Understanding the Magic of Tied Hashes and Arrays> for more
+information on how to use this function on tied hashes.
+
+ SV** hv_fetch (HV* tb, const char* key, U32 klen, I32 lval)
=item hv_fetch_ent
is a pointer to a static location, so be sure to make a copy of the
structure if you need to store it somewhere.
- HE* hv_fetch_ent _((HV* tb, SV* key, I32 lval, U32 hash));
+See L<Understanding the Magic of Tied Hashes and Arrays> for more
+information on how to use this function on tied hashes.
-=item hv_free_ent
-
-Releases a hash entry, such as while iterating though the hash. See
-C<hv_iternext> and C<hv_delayfree_ent>.
-
- void hv_free_ent _((HV* hv, HE* entry));
+ HE* hv_fetch_ent (HV* tb, SV* key, I32 lval, U32 hash)
=item hv_iterinit
Prepares a starting point to traverse a hash table.
- I32 hv_iterinit _((HV* tb));
+ I32 hv_iterinit (HV* tb)
+
+Returns the number of keys in the hash (i.e. the same as C<HvKEYS(tb)>).
+The return value is currently only meaningful for hashes without tie
+magic.
+
+NOTE: Before version 5.004_65, C<hv_iterinit> used to return the number
+of hash buckets that happen to be in use. If you still need that
+esoteric value, you can get it through the macro C<HvFILL(tb)>.
=item hv_iterkey
Returns the key from the current position of the hash iterator. See
C<hv_iterinit>.
- char* hv_iterkey _((HE* entry, I32* retlen));
+ char* hv_iterkey (HE* entry, I32* retlen)
=item hv_iterkeysv
iterator. The return value will always be a mortal copy of the
key. Also see C<hv_iterinit>.
- SV* hv_iterkeysv _((HE* entry));
+ SV* hv_iterkeysv (HE* entry)
=item hv_iternext
Returns entries from a hash iterator. See C<hv_iterinit>.
- HE* hv_iternext _((HV* tb));
+ HE* hv_iternext (HV* tb)
=item hv_iternextsv
Performs an C<hv_iternext>, C<hv_iterkey>, and C<hv_iterval> in one
operation.
- SV * hv_iternextsv _((HV* hv, char** key, I32* retlen));
+ SV* hv_iternextsv (HV* hv, char** key, I32* retlen)
=item hv_iterval
Returns the value from the current position of the hash iterator. See
C<hv_iterkey>.
- SV* hv_iterval _((HV* tb, HE* entry));
+ SV* hv_iterval (HV* tb, HE* entry)
=item hv_magic
Adds magic to a hash. See C<sv_magic>.
- void hv_magic _((HV* hv, GV* gv, int how));
+ void hv_magic (HV* hv, GV* gv, int how)
=item HvNAME
Returns the package name of a stash. See C<SvSTASH>, C<CvSTASH>.
- char *HvNAME (HV* stash)
+ char* HvNAME (HV* stash)
=item hv_store
Stores an SV in a hash. The hash key is specified as C<key> and C<klen> is
the length of the key. The C<hash> parameter is the precomputed hash
value; if it is zero then Perl will compute it. The return value will be
-null if the operation failed, otherwise it can be dereferenced to get the
-original C<SV*>.
+NULL if the operation failed or if the value did not need to be actually
+stored within the hash (as in the case of tied hashes). Otherwise it can
+be dereferenced to get the original C<SV*>. Note that the caller is
+responsible for suitably incrementing the reference count of C<val>
+before the call, and decrementing it if the function returned NULL.
+
+See L<Understanding the Magic of Tied Hashes and Arrays> for more
+information on how to use this function on tied hashes.
- SV** hv_store _((HV* tb, char* key, U32 klen, SV* val, U32 hash));
+ SV** hv_store (HV* tb, const char* key, U32 klen, SV* val, U32 hash)
=item hv_store_ent
Stores C<val> in a hash. The hash key is specified as C<key>. The C<hash>
parameter is the precomputed hash value; if it is zero then Perl will
compute it. The return value is the new hash entry so created. It will be
-null if the operation failed or if the entry was stored in a tied hash.
-Otherwise the contents of the return value can be accessed using the
-C<He???> macros described here.
+NULL if the operation failed or if the value did not need to be actually
+stored within the hash (as in the case of tied hashes). Otherwise the
+contents of the return value can be accessed using the C<He???> macros
+described here. Note that the caller is responsible for suitably
+incrementing the reference count of C<val> before the call, and decrementing
+it if the function returned NULL.
- HE* hv_store_ent _((HV* tb, SV* key, SV* val, U32 hash));
+See L<Understanding the Magic of Tied Hashes and Arrays> for more
+information on how to use this function on tied hashes.
+
+ HE* hv_store_ent (HV* tb, SV* key, SV* val, U32 hash)
=item hv_undef
Undefines the hash.
- void hv_undef _((HV* tb));
+ void hv_undef (HV* tb)
=item isALNUM
Returns a boolean indicating whether the C C<char> is an ascii alphanumeric
character or digit.
- int isALNUM (char c)
+ int isALNUM (char c)
=item isALPHA
Returns a boolean indicating whether the C C<char> is an ascii alphabetic
character.
- int isALPHA (char c)
+ int isALPHA (char c)
=item isDIGIT
Returns a boolean indicating whether the C C<char> is an ascii digit.
- int isDIGIT (char c)
+ int isDIGIT (char c)
=item isLOWER
Returns a boolean indicating whether the C C<char> is a lowercase character.
- int isLOWER (char c)
+ int isLOWER (char c)
=item isSPACE
Returns a boolean indicating whether the C C<char> is whitespace.
- int isSPACE (char c)
+ int isSPACE (char c)
=item isUPPER
Returns a boolean indicating whether the C C<char> is an uppercase character.
- int isUPPER (char c)
+ int isUPPER (char c)
=item items
LEAVE;
+=item looks_like_number
+
+Test if an the content of an SV looks like a number (or is a number).
+
+ int looks_like_number(SV*)
+
+
=item MARK
Stack marker variable for the XSUB. See C<dMARK>.
Clear something magical that the SV represents. See C<sv_magic>.
- int mg_clear _((SV* sv));
+ int mg_clear (SV* sv)
=item mg_copy
Copies the magic from one SV to another. See C<sv_magic>.
- int mg_copy _((SV *, SV *, char *, STRLEN));
+ int mg_copy (SV *, SV *, const char *, STRLEN)
=item mg_find
Finds the magic pointer for type matching the SV. See C<sv_magic>.
- MAGIC* mg_find _((SV* sv, int type));
+ MAGIC* mg_find (SV* sv, int type)
=item mg_free
Free any magic storage used by the SV. See C<sv_magic>.
- int mg_free _((SV* sv));
+ int mg_free (SV* sv)
=item mg_get
Do magic after a value is retrieved from the SV. See C<sv_magic>.
- int mg_get _((SV* sv));
+ int mg_get (SV* sv)
=item mg_len
Report on the SV's length. See C<sv_magic>.
- U32 mg_len _((SV* sv));
+ U32 mg_len (SV* sv)
=item mg_magical
Turns on the magical status of an SV. See C<sv_magic>.
- void mg_magical _((SV* sv));
+ void mg_magical (SV* sv)
=item mg_set
Do magic after a value is assigned to the SV. See C<sv_magic>.
- int mg_set _((SV* sv));
+ int mg_set (SV* sv)
+
+=item modglobal
+
+C<modglobal> is a general purpose, interpreter global HV for use by
+extensions that need to keep information on a per-interpreter basis.
+In a pinch, it can also be used as a symbol table for extensions
+to share data among each other. It is a good idea to use keys
+prefixed by the package name of the extension that owns the data.
=item Move
The XSUB-writer's interface to the C C<memmove> function. The C<s> is the
source, C<d> is the destination, C<n> is the number of items, and C<t> is
-the type.
+the type. Can do overlapping moves. See also C<Copy>.
- (void) Move( s, d, n, t );
+ void Move( s, d, n, t )
-=item na
+=item PL_na
-A variable which may be used with C<SvPV> to tell Perl to calculate the
-string length.
+A convenience variable which is typically used with C<SvPV> when one doesn't
+care about the length of the string. It is usually more efficient to
+either declare a local variable and use that instead or to use the C<SvPV_nolen>
+macro.
=item New
The XSUB-writer's interface to the C C<malloc> function.
- void * New( x, void *ptr, int size, type )
+ void* New( x, void *ptr, int size, type )
-=item Newc
+=item newAV
-The XSUB-writer's interface to the C C<malloc> function, with cast.
+Creates a new AV. The reference count is set to 1.
- void * Newc( x, void *ptr, int size, type, cast )
+ AV* newAV (void)
-=item Newz
+=item Newc
-The XSUB-writer's interface to the C C<malloc> function. The allocated
-memory is zeroed with C<memzero>.
+The XSUB-writer's interface to the C C<malloc> function, with cast.
- void * Newz( x, void *ptr, int size, type )
+ void* Newc( x, void *ptr, int size, type, cast )
-=item newAV
+=item newCONSTSUB
-Creates a new AV. The reference count is set to 1.
+Creates a constant sub equivalent to Perl C<sub FOO () { 123 }>
+which is eligible for inlining at compile-time.
- AV* newAV _((void));
+ void newCONSTSUB(HV* stash, char* name, SV* sv)
=item newHV
Creates a new HV. The reference count is set to 1.
- HV* newHV _((void));
+ HV* newHV (void)
=item newRV_inc
Creates an RV wrapper for an SV. The reference count for the original SV is
incremented.
- SV* newRV_inc _((SV* ref));
+ SV* newRV_inc (SV* ref)
For historical reasons, "newRV" is a synonym for "newRV_inc".
Creates an RV wrapper for an SV. The reference count for the original
SV is B<not> incremented.
- SV* newRV_noinc _((SV* ref));
+ SV* newRV_noinc (SV* ref)
-=item newSV
+=item NEWSV
-Creates a new SV. The C<len> parameter indicates the number of bytes of
-preallocated string space the SV should have. The reference count for the
-new SV is set to 1.
+Creates a new SV. A non-zero C<len> parameter indicates the number of
+bytes of preallocated string space the SV should have. An extra byte
+for a tailing NUL is also reserved. (SvPOK is not set for the SV even
+if string space is allocated.) The reference count for the new SV is
+set to 1. C<id> is an integer id between 0 and 1299 (used to identify
+leaks).
- SV* newSV _((STRLEN len));
+ SV* NEWSV (int id, STRLEN len)
=item newSViv
Creates a new SV and copies an integer into it. The reference count for the
SV is set to 1.
- SV* newSViv _((IV i));
+ SV* newSViv (IV i)
=item newSVnv
Creates a new SV and copies a double into it. The reference count for the
SV is set to 1.
- SV* newSVnv _((NV i));
+ SV* newSVnv (NV i)
=item newSVpv
Creates a new SV and copies a string into it. The reference count for the
-SV is set to 1. If C<len> is zero then Perl will compute the length.
+SV is set to 1. If C<len> is zero, Perl will compute the length using
+strlen(). For efficiency, consider using C<newSVpvn> instead.
+
+ SV* newSVpv (const char* s, STRLEN len)
- SV* newSVpv _((char* s, STRLEN len));
+=item newSVpvf
+
+Creates a new SV an initialize it with the string formatted like
+C<sprintf>.
+
+ SV* newSVpvf(const char* pat, ...)
+
+=item newSVpvn
+
+Creates a new SV and copies a string into it. The reference count for the
+SV is set to 1. Note that if C<len> is zero, Perl will create a zero length
+string. You are responsible for ensuring that the source string is at least
+C<len> bytes long.
+
+ SV* newSVpvn (const char* s, STRLEN len)
=item newSVrv
be blessed in the specified package. The new SV is returned and its
reference count is 1.
- SV* newSVrv _((SV* rv, char* classname));
+ SV* newSVrv (SV* rv, const char* classname)
=item newSVsv
Creates a new SV which is an exact duplicate of the original SV.
- SV* newSVsv _((SV* old));
+ SV* newSVsv (SV* old)
=item newXS
Used by C<xsubpp> to hook up XSUBs as Perl subs. Adds Perl prototypes to
the subs.
+=item Newz
+
+The XSUB-writer's interface to the C C<malloc> function. The allocated
+memory is zeroed with C<memzero>.
+
+ void* Newz( x, void *ptr, int size, type )
+
=item Nullav
Null AV pointer.
Performs a callback to the specified Perl sub. See L<perlcall>.
- I32 perl_call_argv _((char* subname, I32 flags, char** argv));
+ I32 perl_call_argv (const char* subname, I32 flags, char** argv)
=item perl_call_method
Performs a callback to the specified Perl method. The blessed object must
be on the stack. See L<perlcall>.
- I32 perl_call_method _((char* methname, I32 flags));
+ I32 perl_call_method (const char* methname, I32 flags)
=item perl_call_pv
Performs a callback to the specified Perl sub. See L<perlcall>.
- I32 perl_call_pv _((char* subname, I32 flags));
+ I32 perl_call_pv (const char* subname, I32 flags)
=item perl_call_sv
Performs a callback to the Perl sub whose name is in the SV. See
L<perlcall>.
- I32 perl_call_sv _((SV* sv, I32 flags));
+ I32 perl_call_sv (SV* sv, I32 flags)
=item perl_construct
Tells Perl to C<eval> the string in the SV.
- I32 perl_eval_sv _((SV* sv, I32 flags));
+ I32 perl_eval_sv (SV* sv, I32 flags)
=item perl_eval_pv
Tells Perl to C<eval> the given string and return an SV* result.
- SV* perl_eval_pv _((char* p, I32 croak_on_error));
+ SV* perl_eval_pv (const char* p, I32 croak_on_error)
=item perl_free
Returns the AV of the specified Perl array. If C<create> is set and the
Perl variable does not exist then it will be created. If C<create> is not
-set and the variable does not exist then null is returned.
+set and the variable does not exist then NULL is returned.
- AV* perl_get_av _((char* name, I32 create));
+ AV* perl_get_av (const char* name, I32 create)
=item perl_get_cv
-Returns the CV of the specified Perl sub. If C<create> is set and the Perl
-variable does not exist then it will be created. If C<create> is not
-set and the variable does not exist then null is returned.
+Returns the CV of the specified Perl subroutine. If C<create> is set and
+the Perl subroutine does not exist then it will be declared (which has
+the same effect as saying C<sub name;>). If C<create> is not
+set and the subroutine does not exist then NULL is returned.
- CV* perl_get_cv _((char* name, I32 create));
+ CV* perl_get_cv (const char* name, I32 create)
=item perl_get_hv
Returns the HV of the specified Perl hash. If C<create> is set and the Perl
variable does not exist then it will be created. If C<create> is not
-set and the variable does not exist then null is returned.
+set and the variable does not exist then NULL is returned.
- HV* perl_get_hv _((char* name, I32 create));
+ HV* perl_get_hv (const char* name, I32 create)
=item perl_get_sv
Returns the SV of the specified Perl scalar. If C<create> is set and the
Perl variable does not exist then it will be created. If C<create> is not
-set and the variable does not exist then null is returned.
+set and the variable does not exist then NULL is returned.
- SV* perl_get_sv _((char* name, I32 create));
+ SV* perl_get_sv (const char* name, I32 create)
=item perl_parse
Tells Perl to C<require> a module.
- void perl_require_pv _((char* pv));
+ void perl_require_pv (const char* pv)
=item perl_run
Pops an integer off the stack.
- int POPi();
+ int POPi()
=item POPl
Pops a long off the stack.
- long POPl();
+ long POPl()
=item POPp
Pops a string off the stack.
- char * POPp();
+ char* POPp()
=item POPn
Pops a double off the stack.
- double POPn();
+ double POPn()
=item POPs
Pops an SV off the stack.
- SV* POPs();
+ SV* POPs()
=item PUSHMARK
=item PUSHi
Push an integer onto the stack. The stack must have room for this element.
-See C<XPUSHi>.
+Handles 'set' magic. See C<XPUSHi>.
- PUSHi(int d)
+ void PUSHi(int d)
=item PUSHn
Push a double onto the stack. The stack must have room for this element.
-See C<XPUSHn>.
+Handles 'set' magic. See C<XPUSHn>.
- PUSHn(double d)
+ void PUSHn(double d)
=item PUSHp
Push a string onto the stack. The stack must have room for this element.
-The C<len> indicates the length of the string. See C<XPUSHp>.
+The C<len> indicates the length of the string. Handles 'set' magic. See
+C<XPUSHp>.
- PUSHp(char *c, int len )
+ void PUSHp(char *c, int len )
=item PUSHs
-Push an SV onto the stack. The stack must have room for this element. See
-C<XPUSHs>.
+Push an SV onto the stack. The stack must have room for this element. Does
+not handle 'set' magic. See C<XPUSHs>.
+
+ void PUSHs(sv)
+
+=item PUSHu
+
+Push an unsigned integer onto the stack. The stack must have room for
+this element. See C<XPUSHu>.
+
+ void PUSHu(unsigned int d)
- PUSHs(sv)
=item PUTBACK
The XSUB-writer's interface to the C C<realloc> function.
- void * Renew( void *ptr, int size, type )
+ void* Renew( void *ptr, int size, type )
=item Renewc
The XSUB-writer's interface to the C C<realloc> function, with cast.
- void * Renewc( void *ptr, int size, type, cast )
+ void* Renewc( void *ptr, int size, type, cast )
=item RETVAL
Copy a string to a safe spot. This does not use an SV.
- char* savepv _((char* sv));
+ char* savepv (const char* sv)
=item savepvn
Copy a string to a safe spot. The C<len> indicates number of bytes to
copy. This does not use an SV.
- char* savepvn _((char* sv, I32 len));
+ char* savepvn (const char* sv, I32 len)
=item SAVETMPS
Used to access elements on the XSUB's stack.
- SV* ST(int x)
+ SV* ST(int x)
=item strEQ
Test two strings to see if they are equal. Returns true or false.
- int strEQ( char *s1, char *s2 )
+ int strEQ( char *s1, char *s2 )
=item strGE
Test two strings to see if the first, C<s1>, is greater than or equal to the
second, C<s2>. Returns true or false.
- int strGE( char *s1, char *s2 )
+ int strGE( char *s1, char *s2 )
=item strGT
Test two strings to see if the first, C<s1>, is greater than the second,
C<s2>. Returns true or false.
- int strGT( char *s1, char *s2 )
+ int strGT( char *s1, char *s2 )
=item strLE
Test two strings to see if the first, C<s1>, is less than or equal to the
second, C<s2>. Returns true or false.
- int strLE( char *s1, char *s2 )
+ int strLE( char *s1, char *s2 )
=item strLT
Test two strings to see if the first, C<s1>, is less than the second,
C<s2>. Returns true or false.
- int strLT( char *s1, char *s2 )
+ int strLT( char *s1, char *s2 )
=item strNE
Test two strings to see if they are different. Returns true or false.
- int strNE( char *s1, char *s2 )
+ int strNE( char *s1, char *s2 )
=item strnEQ
Test two strings to see if they are equal. The C<len> parameter indicates
the number of bytes to compare. Returns true or false.
- int strnEQ( char *s1, char *s2 )
+ int strnEQ( char *s1, char *s2 )
=item strnNE
Test two strings to see if they are different. The C<len> parameter
indicates the number of bytes to compare. Returns true or false.
- int strnNE( char *s1, char *s2, int len )
+ int strnNE( char *s1, char *s2, int len )
=item sv_2mortal
Marks an SV as mortal. The SV will be destroyed when the current context
ends.
- SV* sv_2mortal _((SV* sv));
+ SV* sv_2mortal (SV* sv)
=item sv_bless
must be designated by its stash (see C<gv_stashpv()>). The reference count
of the SV is unaffected.
- SV* sv_bless _((SV* sv, HV* stash));
+ SV* sv_bless (SV* sv, HV* stash)
=item sv_catpv
Concatenates the string onto the end of the string which is in the SV.
+Handles 'get' magic, but not 'set' magic. See C<sv_catpv_mg>.
+
+ void sv_catpv (SV* sv, const char* ptr)
+
+=item sv_catpv_mg
- void sv_catpv _((SV* sv, char* ptr));
+Like C<sv_catpv>, but also handles 'set' magic.
+
+ void sv_catpvn (SV* sv, const char* ptr)
=item sv_catpvn
Concatenates the string onto the end of the string which is in the SV. The
-C<len> indicates number of bytes to copy.
+C<len> indicates number of bytes to copy. Handles 'get' magic, but not
+'set' magic. See C<sv_catpvn_mg>.
+
+ void sv_catpvn (SV* sv, const char* ptr, STRLEN len)
+
+=item sv_catpvn_mg
+
+Like C<sv_catpvn>, but also handles 'set' magic.
- void sv_catpvn _((SV* sv, char* ptr, STRLEN len));
+ void sv_catpvn_mg (SV* sv, const char* ptr, STRLEN len)
+
+=item sv_catpvf
+
+Processes its arguments like C<sprintf> and appends the formatted output
+to an SV. Handles 'get' magic, but not 'set' magic. C<SvSETMAGIC()> must
+typically be called after calling this function to handle 'set' magic.
+
+ void sv_catpvf (SV* sv, const char* pat, ...)
+
+=item sv_catpvf_mg
+
+Like C<sv_catpvf>, but also handles 'set' magic.
+
+ void sv_catpvf_mg (SV* sv, const char* pat, ...)
=item sv_catsv
Concatenates the string from SV C<ssv> onto the end of the string in SV
-C<dsv>.
+C<dsv>. Handles 'get' magic, but not 'set' magic. See C<sv_catsv_mg>.
- void sv_catsv _((SV* dsv, SV* ssv));
+ void sv_catsv (SV* dsv, SV* ssv)
-=item sv_cmp
+=item sv_catsv_mg
-Compares the strings in two SVs. Returns -1, 0, or 1 indicating whether the
-string in C<sv1> is less than, equal to, or greater than the string in
-C<sv2>.
+Like C<sv_catsv>, but also handles 'set' magic.
+
+ void sv_catsv_mg (SV* dsv, SV* ssv)
+
+=item sv_chop
+
+Efficient removal of characters from the beginning of the string
+buffer. SvPOK(sv) must be true and the C<ptr> must be a pointer to
+somewhere inside the string buffer. The C<ptr> becomes the first
+character of the adjusted string.
+
+ void sv_chop(SV* sv, const char *ptr)
- I32 sv_cmp _((SV* sv1, SV* sv2));
=item sv_cmp
string in C<sv1> is less than, equal to, or greater than the string in
C<sv2>.
- I32 sv_cmp _((SV* sv1, SV* sv2));
+ I32 sv_cmp (SV* sv1, SV* sv2)
=item SvCUR
Returns the length of the string which is in the SV. See C<SvLEN>.
- int SvCUR (SV* sv)
+ int SvCUR (SV* sv)
=item SvCUR_set
Set the length of the string which is in the SV. See C<SvCUR>.
- SvCUR_set (SV* sv, int val )
+ void SvCUR_set (SV* sv, int val)
=item sv_dec
Auto-decrement of the value in the SV.
- void sv_dec _((SV* sv));
+ void sv_dec (SV* sv)
-=item sv_dec
+=item sv_derived_from
-Auto-decrement of the value in the SV.
+Returns a boolean indicating whether the SV is derived from the specified
+class. This is the function that implements C<UNIVERSAL::isa>. It works
+for class names as well as for objects.
- void sv_dec _((SV* sv));
+ bool sv_derived_from (SV* sv, const char* name);
=item SvEND
Returns a pointer to the last character in the string which is in the SV.
See C<SvCUR>. Access the character as
- *SvEND(sv)
+ char* SvEND(sv)
=item sv_eq
Returns a boolean indicating whether the strings in the two SVs are
identical.
- I32 sv_eq _((SV* sv1, SV* sv2));
+ I32 sv_eq (SV* sv1, SV* sv2)
+
+=item SvGETMAGIC
+
+Invokes C<mg_get> on an SV if it has 'get' magic. This macro evaluates
+its argument more than once.
+
+ void SvGETMAGIC(SV *sv)
=item SvGROW
-Expands the character buffer in the SV. Calls C<sv_grow> to perform the
-expansion if necessary. Returns a pointer to the character buffer.
+Expands the character buffer in the SV so that it has room for the
+indicated number of bytes (remember to reserve space for an extra
+trailing NUL character). Calls C<sv_grow> to perform the expansion if
+necessary. Returns a pointer to the character buffer.
- char * SvGROW( SV* sv, int len )
+ char* SvGROW(SV* sv, STRLEN len)
=item sv_grow
Auto-increment of the value in the SV.
- void sv_inc _((SV* sv));
+ void sv_inc (SV* sv)
+
+=item sv_insert
+
+Inserts a string at the specified offset/length within the SV.
+Similar to the Perl substr() function.
+
+ void sv_insert(SV *sv, STRLEN offset, STRLEN len,
+ char *str, STRLEN strlen)
=item SvIOK
Returns a boolean indicating whether the SV contains an integer.
- int SvIOK (SV* SV)
+ int SvIOK (SV* SV)
=item SvIOK_off
Unsets the IV status of an SV.
- SvIOK_off (SV* sv)
+ void SvIOK_off (SV* sv)
=item SvIOK_on
Tells an SV that it is an integer.
- SvIOK_on (SV* sv)
-
-=item SvIOK_only
-
-Tells an SV that it is an integer and disables all other OK bits.
-
- SvIOK_on (SV* sv)
+ void SvIOK_on (SV* sv)
=item SvIOK_only
Tells an SV that it is an integer and disables all other OK bits.
- SvIOK_on (SV* sv)
+ void SvIOK_only (SV* sv)
=item SvIOKp
Returns a boolean indicating whether the SV contains an integer. Checks the
B<private> setting. Use C<SvIOK>.
- int SvIOKp (SV* SV)
+ int SvIOKp (SV* SV)
=item sv_isa
Returns a boolean indicating whether the SV is blessed into the specified
-class. This does not know how to check for subtype, so it doesn't work in
+class. This does not check for subtypes; use C<sv_derived_from> to verify
an inheritance relationship.
- int sv_isa _((SV* sv, char* name));
-
-=item SvIV
-
-Returns the integer which is in the SV.
-
- int SvIV (SV* sv)
+ int sv_isa (SV* sv, char* name)
=item sv_isobject
object. If the SV is not an RV, or if the object is not blessed, then this
will return false.
- int sv_isobject _((SV* sv));
+ int sv_isobject (SV* sv)
-=item SvIVX
+=item SvIV
-Returns the integer which is stored in the SV.
+Coerces the given SV to an integer and returns it.
- int SvIVX (SV* sv);
+ int SvIV (SV* sv)
-=item SvLEN
+=item SvIVX
-Returns the size of the string buffer in the SV. See C<SvCUR>.
+Returns the integer which is stored in the SV, assuming SvIOK is true.
- int SvLEN (SV* sv)
+ int SvIVX (SV* sv)
-=item sv_len
+=item SvLEN
-Returns the length of the string in the SV. Use C<SvCUR>.
+Returns the size of the string buffer in the SV. See C<SvCUR>.
- STRLEN sv_len _((SV* sv));
+ int SvLEN (SV* sv)
=item sv_len
Returns the length of the string in the SV. Use C<SvCUR>.
- STRLEN sv_len _((SV* sv));
+ STRLEN sv_len (SV* sv)
=item sv_magic
Adds magic to an SV.
- void sv_magic _((SV* sv, SV* obj, int how, char* name, I32 namlen));
+ void sv_magic (SV* sv, SV* obj, int how, const char* name, I32 namlen)
=item sv_mortalcopy
Creates a new SV which is a copy of the original SV. The new SV is marked
as mortal.
- SV* sv_mortalcopy _((SV* oldsv));
-
-=item SvOK
-
-Returns a boolean indicating whether the value is an SV.
-
- int SvOK (SV* sv)
+ SV* sv_mortalcopy (SV* oldsv)
=item sv_newmortal
Creates a new SV which is mortal. The reference count of the SV is set to 1.
- SV* sv_newmortal _((void));
-
-=item sv_no
-
-This is the C<false> SV. See C<sv_yes>. Always refer to this as C<&sv_no>.
+ SV* sv_newmortal (void)
=item SvNIOK
Returns a boolean indicating whether the SV contains a number, integer or
double.
- int SvNIOK (SV* SV)
+ int SvNIOK (SV* SV)
=item SvNIOK_off
Unsets the NV/IV status of an SV.
- SvNIOK_off (SV* sv)
+ void SvNIOK_off (SV* sv)
=item SvNIOKp
Returns a boolean indicating whether the SV contains a number, integer or
double. Checks the B<private> setting. Use C<SvNIOK>.
- int SvNIOKp (SV* SV)
+ int SvNIOKp (SV* SV)
+
+=item PL_sv_no
+
+This is the C<false> SV. See C<PL_sv_yes>. Always refer to this as C<&PL_sv_no>.
=item SvNOK
Returns a boolean indicating whether the SV contains a double.
- int SvNOK (SV* SV)
+ int SvNOK (SV* SV)
=item SvNOK_off
Unsets the NV status of an SV.
- SvNOK_off (SV* sv)
+ void SvNOK_off (SV* sv)
=item SvNOK_on
Tells an SV that it is a double.
- SvNOK_on (SV* sv)
-
-=item SvNOK_only
-
-Tells an SV that it is a double and disables all other OK bits.
-
- SvNOK_on (SV* sv)
+ void SvNOK_on (SV* sv)
=item SvNOK_only
Tells an SV that it is a double and disables all other OK bits.
- SvNOK_on (SV* sv)
+ void SvNOK_only (SV* sv)
=item SvNOKp
Returns a boolean indicating whether the SV contains a double. Checks the
B<private> setting. Use C<SvNOK>.
- int SvNOKp (SV* SV)
+ int SvNOKp (SV* SV)
=item SvNV
-Returns the double which is stored in the SV.
+Coerce the given SV to a double and return it.
- double SvNV (SV* sv);
+ double SvNV (SV* sv)
=item SvNVX
-Returns the double which is stored in the SV.
+Returns the double which is stored in the SV, assuming SvNOK is true.
- double SvNVX (SV* sv);
+ double SvNVX (SV* sv)
+
+=item SvOK
+
+Returns a boolean indicating whether the value is an SV.
+
+ int SvOK (SV* sv)
+
+=item SvOOK
+
+Returns a boolean indicating whether the SvIVX is a valid offset value
+for the SvPVX. This hack is used internally to speed up removal of
+characters from the beginning of a SvPV. When SvOOK is true, then the
+start of the allocated string buffer is really (SvPVX - SvIVX).
+
+ int SvOOK(SV* sv)
=item SvPOK
Returns a boolean indicating whether the SV contains a character string.
- int SvPOK (SV* SV)
+ int SvPOK (SV* SV)
=item SvPOK_off
Unsets the PV status of an SV.
- SvPOK_off (SV* sv)
+ void SvPOK_off (SV* sv)
=item SvPOK_on
Tells an SV that it is a string.
- SvPOK_on (SV* sv)
+ void SvPOK_on (SV* sv)
=item SvPOK_only
Tells an SV that it is a string and disables all other OK bits.
- SvPOK_on (SV* sv)
-
-=item SvPOK_only
-
-Tells an SV that it is a string and disables all other OK bits.
-
- SvPOK_on (SV* sv)
+ void SvPOK_only (SV* sv)
=item SvPOKp
Returns a boolean indicating whether the SV contains a character string.
Checks the B<private> setting. Use C<SvPOK>.
- int SvPOKp (SV* SV)
+ int SvPOKp (SV* SV)
=item SvPV
Returns a pointer to the string in the SV, or a stringified form of the SV
-if the SV does not contain a string. If C<len> is C<na> then Perl will
-handle the length on its own.
+if the SV does not contain a string. Handles 'get' magic.
+
+ char* SvPV (SV* sv, STRLEN len)
+
+=item SvPV_force
- char * SvPV (SV* sv, int len )
+Like <SvPV> but will force the SV into becoming a string (SvPOK). You
+want force if you are going to update the SvPVX directly.
+
+ char* SvPV_force(SV* sv, STRLEN len)
+
+=item SvPV_nolen
+
+Returns a pointer to the string in the SV, or a stringified form of the SV
+if the SV does not contain a string. Handles 'get' magic.
+
+ char* SvPV_nolen (SV* sv)
=item SvPVX
Returns a pointer to the string in the SV. The SV must contain a string.
- char * SvPVX (SV* sv)
+ char* SvPVX (SV* sv)
=item SvREFCNT
Returns the value of the object's reference count.
- int SvREFCNT (SV* sv);
+ int SvREFCNT (SV* sv)
=item SvREFCNT_dec
Decrements the reference count of the given SV.
- void SvREFCNT_dec (SV* sv)
+ void SvREFCNT_dec (SV* sv)
=item SvREFCNT_inc
Increments the reference count of the given SV.
- void SvREFCNT_inc (SV* sv)
+ void SvREFCNT_inc (SV* sv)
=item SvROK
Tests if the SV is an RV.
- int SvROK (SV* sv)
+ int SvROK (SV* sv)
=item SvROK_off
Unsets the RV status of an SV.
- SvROK_off (SV* sv)
+ void SvROK_off (SV* sv)
=item SvROK_on
Tells an SV that it is an RV.
- SvROK_on (SV* sv)
+ void SvROK_on (SV* sv)
=item SvRV
Dereferences an RV to return the SV.
- SV* SvRV (SV* sv);
+ SV* SvRV (SV* sv)
+
+=item SvSETMAGIC
+
+Invokes C<mg_set> on an SV if it has 'set' magic. This macro evaluates
+its argument more than once.
+
+ void SvSETMAGIC( SV *sv )
=item sv_setiv
-Copies an integer into the given SV.
+Copies an integer into the given SV. Does not handle 'set' magic.
+See C<sv_setiv_mg>.
+
+ void sv_setiv (SV* sv, IV num)
- void sv_setiv _((SV* sv, IV num));
+=item sv_setiv_mg
+
+Like C<sv_setiv>, but also handles 'set' magic.
+
+ void sv_setiv_mg (SV* sv, IV num)
=item sv_setnv
-Copies a double into the given SV.
+Copies a double into the given SV. Does not handle 'set' magic.
+See C<sv_setnv_mg>.
+
+ void sv_setnv (SV* sv, double num)
+
+=item sv_setnv_mg
- void sv_setnv _((SV* sv, double num));
+Like C<sv_setnv>, but also handles 'set' magic.
+
+ void sv_setnv_mg (SV* sv, double num)
=item sv_setpv
Copies a string into an SV. The string must be null-terminated.
+Does not handle 'set' magic. See C<sv_setpv_mg>.
+
+ void sv_setpv (SV* sv, const char* ptr)
+
+=item sv_setpv_mg
+
+Like C<sv_setpv>, but also handles 'set' magic.
+
+ void sv_setpv_mg (SV* sv, const char* ptr)
+
+=item sv_setpviv
+
+Copies an integer into the given SV, also updating its string value.
+Does not handle 'set' magic. See C<sv_setpviv_mg>.
+
+ void sv_setpviv (SV* sv, IV num)
+
+=item sv_setpviv_mg
- void sv_setpv _((SV* sv, char* ptr));
+Like C<sv_setpviv>, but also handles 'set' magic.
+
+ void sv_setpviv_mg (SV* sv, IV num)
=item sv_setpvn
Copies a string into an SV. The C<len> parameter indicates the number of
-bytes to be copied.
+bytes to be copied. Does not handle 'set' magic. See C<sv_setpvn_mg>.
+
+ void sv_setpvn (SV* sv, const char* ptr, STRLEN len)
+
+=item sv_setpvn_mg
+
+Like C<sv_setpvn>, but also handles 'set' magic.
+
+ void sv_setpvn_mg (SV* sv, const char* ptr, STRLEN len)
+
+=item sv_setpvf
+
+Processes its arguments like C<sprintf> and sets an SV to the formatted
+output. Does not handle 'set' magic. See C<sv_setpvf_mg>.
+
+ void sv_setpvf (SV* sv, const char* pat, ...)
+
+=item sv_setpvf_mg
+
+Like C<sv_setpvf>, but also handles 'set' magic.
- void sv_setpvn _((SV* sv, char* ptr, STRLEN len));
+ void sv_setpvf_mg (SV* sv, const char* pat, ...)
=item sv_setref_iv
blessing. Set C<classname> to C<Nullch> to avoid the blessing. The new SV
will be returned and will have a reference count of 1.
- SV* sv_setref_iv _((SV *rv, char *classname, IV iv));
+ SV* sv_setref_iv (SV *rv, char *classname, IV iv)
=item sv_setref_nv
blessing. Set C<classname> to C<Nullch> to avoid the blessing. The new SV
will be returned and will have a reference count of 1.
- SV* sv_setref_nv _((SV *rv, char *classname, double nv));
+ SV* sv_setref_nv (SV *rv, char *classname, double nv)
=item sv_setref_pv
Copies a pointer into a new SV, optionally blessing the SV. The C<rv>
argument will be upgraded to an RV. That RV will be modified to point to
-the new SV. If the C<pv> argument is NULL then C<sv_undef> will be placed
+the new SV. If the C<pv> argument is NULL then C<PL_sv_undef> will be placed
into the SV. The C<classname> argument indicates the package for the
blessing. Set C<classname> to C<Nullch> to avoid the blessing. The new SV
will be returned and will have a reference count of 1.
- SV* sv_setref_pv _((SV *rv, char *classname, void* pv));
+ SV* sv_setref_pv (SV *rv, char *classname, void* pv)
Do not use with integral Perl types such as HV, AV, SV, CV, because those
objects will become corrupted by the pointer copy process.
C<Nullch> to avoid the blessing. The new SV will be returned and will have
a reference count of 1.
- SV* sv_setref_pvn _((SV *rv, char *classname, char* pv, I32 n));
+ SV* sv_setref_pvn (SV *rv, char *classname, char* pv, I32 n)
Note that C<sv_setref_pv> copies the pointer while this copies the string.
+=item SvSetSV
+
+Calls C<sv_setsv> if dsv is not the same as ssv. May evaluate arguments
+more than once.
+
+ void SvSetSV (SV* dsv, SV* ssv)
+
+=item SvSetSV_nosteal
+
+Calls a non-destructive version of C<sv_setsv> if dsv is not the same as ssv.
+May evaluate arguments more than once.
+
+ void SvSetSV_nosteal (SV* dsv, SV* ssv)
+
=item sv_setsv
Copies the contents of the source SV C<ssv> into the destination SV C<dsv>.
-The source SV may be destroyed if it is mortal.
+The source SV may be destroyed if it is mortal. Does not handle 'set' magic.
+See the macro forms C<SvSetSV>, C<SvSetSV_nosteal> and C<sv_setsv_mg>.
+
+ void sv_setsv (SV* dsv, SV* ssv)
+
+=item sv_setsv_mg
+
+Like C<sv_setsv>, but also handles 'set' magic.
- void sv_setsv _((SV* dsv, SV* ssv));
+ void sv_setsv_mg (SV* dsv, SV* ssv)
+
+=item sv_setuv
+
+Copies an unsigned integer into the given SV. Does not handle 'set' magic.
+See C<sv_setuv_mg>.
+
+ void sv_setuv (SV* sv, UV num)
+
+=item sv_setuv_mg
+
+Like C<sv_setuv>, but also handles 'set' magic.
+
+ void sv_setuv_mg (SV* sv, UV num)
=item SvSTASH
Returns the stash of the SV.
- HV * SvSTASH (SV* sv)
+ HV* SvSTASH (SV* sv)
+
+=item SvTAINT
+
+Taints an SV if tainting is enabled
+
+ void SvTAINT (SV* sv)
+
+=item SvTAINTED
+
+Checks to see if an SV is tainted. Returns TRUE if it is, FALSE if not.
+
+ int SvTAINTED (SV* sv)
+
+=item SvTAINTED_off
+
+Untaints an SV. Be I<very> careful with this routine, as it short-circuits
+some of Perl's fundamental security features. XS module authors should
+not use this function unless they fully understand all the implications
+of unconditionally untainting the value. Untainting should be done in
+the standard perl fashion, via a carefully crafted regexp, rather than
+directly untainting variables.
+
+ void SvTAINTED_off (SV* sv)
+
+=item SvTAINTED_on
+
+Marks an SV as tainted.
+
+ void SvTAINTED_on (SV* sv)
=item SVt_IV
=item SvTRUE
Returns a boolean indicating whether Perl would evaluate the SV as true or
-false, defined or undefined.
+false, defined or undefined. Does not handle 'get' magic.
- int SvTRUE (SV* sv)
+ int SvTRUE (SV* sv)
=item SvTYPE
An enum of flags for Perl types. These are found in the file B<sv.h> in the
C<svtype> enum. Test these flags with the C<SvTYPE> macro.
-=item SvUPGRADE
+=item PL_sv_undef
-Used to upgrade an SV to a more complex form. Uses C<sv_upgrade> to perform
-the upgrade if necessary. See C<svtype>.
+This is the C<undef> SV. Always refer to this as C<&PL_sv_undef>.
- bool SvUPGRADE _((SV* sv, svtype mt));
+=item sv_unref
-=item sv_upgrade
+Unsets the RV status of the SV, and decrements the reference count of
+whatever was being referenced by the RV. This can almost be thought of
+as a reversal of C<newSVrv>. See C<SvROK_off>.
-Upgrade an SV to a more complex form. Use C<SvUPGRADE>. See C<svtype>.
+ void sv_unref (SV* sv)
-=item sv_undef
+=item SvUPGRADE
-This is the C<undef> SV. Always refer to this as C<&sv_undef>.
+Used to upgrade an SV to a more complex form. Uses C<sv_upgrade> to perform
+the upgrade if necessary. See C<svtype>.
-=item sv_unref
+ bool SvUPGRADE (SV* sv, svtype mt)
-Unsets the RV status of the SV, and decrements the reference count of
-whatever was being referenced by the RV. This can almost be thought of
-as a reversal of C<newSVrv>. See C<SvROK_off>.
+=item sv_upgrade
- void sv_unref _((SV* sv));
+Upgrade an SV to a more complex form. Use C<SvUPGRADE>. See C<svtype>.
=item sv_usepvn
The C<ptr> should point to memory that was allocated by C<malloc>. The
string length, C<len>, must be supplied. This function will realloc the
memory pointed to by C<ptr>, so that pointer should not be freed or used by
-the programmer after giving it to sv_usepvn.
+the programmer after giving it to sv_usepvn. Does not handle 'set' magic.
+See C<sv_usepvn_mg>.
+
+ void sv_usepvn (SV* sv, char* ptr, STRLEN len)
- void sv_usepvn _((SV* sv, char* ptr, STRLEN len));
+=item sv_usepvn_mg
-=item sv_yes
+Like C<sv_usepvn>, but also handles 'set' magic.
-This is the C<true> SV. See C<sv_no>. Always refer to this as C<&sv_yes>.
+ void sv_usepvn_mg (SV* sv, char* ptr, STRLEN len)
+
+=item sv_vcatpvfn(sv, pat, patlen, args, svargs, svmax, used_locale)
+
+Processes its arguments like C<vsprintf> and appends the formatted output
+to an SV. Uses an array of SVs if the C style variable argument list is
+missing (NULL). Indicates if locale information has been used for formatting.
+
+ void sv_catpvfn (SV* sv, const char* pat, STRLEN patlen,
+ va_list *args, SV **svargs, I32 svmax,
+ bool *used_locale);
+
+=item sv_vsetpvfn(sv, pat, patlen, args, svargs, svmax, used_locale)
+
+Works like C<vcatpvfn> but copies the text into the SV instead of
+appending it.
+
+ void sv_setpvfn (SV* sv, const char* pat, STRLEN patlen,
+ va_list *args, SV **svargs, I32 svmax,
+ bool *used_locale);
+
+=item SvUV
+
+Coerces the given SV to an unsigned integer and returns it.
+
+ UV SvUV(SV* sv)
+
+=item SvUVX
+
+Returns the unsigned integer which is stored in the SV, assuming SvIOK is true.
+
+ UV SvUVX(SV* sv)
+
+=item PL_sv_yes
+
+This is the C<true> SV. See C<PL_sv_no>. Always refer to this as C<&PL_sv_yes>.
=item THIS
Converts the specified character to lowercase.
- int toLOWER (char c)
+ int toLOWER (char c)
=item toUPPER
Converts the specified character to uppercase.
- int toUPPER (char c)
+ int toUPPER (char c)
=item warn
=item XPUSHi
-Push an integer onto the stack, extending the stack if necessary. See
-C<PUSHi>.
+Push an integer onto the stack, extending the stack if necessary. Handles
+'set' magic. See C<PUSHi>.
XPUSHi(int d)
=item XPUSHn
-Push a double onto the stack, extending the stack if necessary. See
-C<PUSHn>.
+Push a double onto the stack, extending the stack if necessary. Handles 'set'
+magic. See C<PUSHn>.
XPUSHn(double d)
=item XPUSHp
Push a string onto the stack, extending the stack if necessary. The C<len>
-indicates the length of the string. See C<PUSHp>.
+indicates the length of the string. Handles 'set' magic. See C<PUSHp>.
XPUSHp(char *c, int len)
=item XPUSHs
-Push an SV onto the stack, extending the stack if necessary. See C<PUSHs>.
+Push an SV onto the stack, extending the stack if necessary. Does not
+handle 'set' magic. See C<PUSHs>.
XPUSHs(sv)
+=item XPUSHu
+
+Push an unsigned integer onto the stack, extending the stack if
+necessary. See C<PUSHu>.
+
=item XS
Macro to declare an XSUB and its C parameter list. This is handled by
Return from XSUB, indicating number of items on the stack. This is usually
handled by C<xsubpp>.
- XSRETURN(int x);
+ XSRETURN(int x)
=item XSRETURN_EMPTY
Return an integer from an XSUB immediately. Uses C<XST_mIV>.
- XSRETURN_IV(IV v);
+ XSRETURN_IV(IV v)
=item XSRETURN_NO
-Return C<&sv_no> from an XSUB immediately. Uses C<XST_mNO>.
+Return C<&PL_sv_no> from an XSUB immediately. Uses C<XST_mNO>.
XSRETURN_NO;
Return an double from an XSUB immediately. Uses C<XST_mNV>.
- XSRETURN_NV(NV v);
+ XSRETURN_NV(NV v)
=item XSRETURN_PV
Return a copy of a string from an XSUB immediately. Uses C<XST_mPV>.
- XSRETURN_PV(char *v);
+ XSRETURN_PV(char *v)
=item XSRETURN_UNDEF
-Return C<&sv_undef> from an XSUB immediately. Uses C<XST_mUNDEF>.
+Return C<&PL_sv_undef> from an XSUB immediately. Uses C<XST_mUNDEF>.
XSRETURN_UNDEF;
=item XSRETURN_YES
-Return C<&sv_yes> from an XSUB immediately. Uses C<XST_mYES>.
+Return C<&PL_sv_yes> from an XSUB immediately. Uses C<XST_mYES>.
XSRETURN_YES;
Place an integer into the specified position C<i> on the stack. The value is
stored in a new mortal SV.
- XST_mIV( int i, IV v );
+ XST_mIV( int i, IV v )
=item XST_mNV
Place a double into the specified position C<i> on the stack. The value is
stored in a new mortal SV.
- XST_mNV( int i, NV v );
+ XST_mNV( int i, NV v )
=item XST_mNO
-Place C<&sv_no> into the specified position C<i> on the stack.
+Place C<&PL_sv_no> into the specified position C<i> on the stack.
- XST_mNO( int i );
+ XST_mNO( int i )
=item XST_mPV
Place a copy of a string into the specified position C<i> on the stack. The
value is stored in a new mortal SV.
- XST_mPV( int i, char *v );
+ XST_mPV( int i, char *v )
=item XST_mUNDEF
-Place C<&sv_undef> into the specified position C<i> on the stack.
+Place C<&PL_sv_undef> into the specified position C<i> on the stack.
- XST_mUNDEF( int i );
+ XST_mUNDEF( int i )
=item XST_mYES
-Place C<&sv_yes> into the specified position C<i> on the stack.
+Place C<&PL_sv_yes> into the specified position C<i> on the stack.
- XST_mYES( int i );
+ XST_mYES( int i )
=item XS_VERSION
The XSUB-writer's interface to the C C<memzero> function. The C<d> is the
destination, C<n> is the number of items, and C<t> is the type.
- (void) Zero( d, n, t );
+ void Zero( d, n, t )
=back
-=head1 EDITOR
+=head1 AUTHORS
-Jeff Okamoto <F<okamoto@corp.hp.com>>
+Until May 1997, this document was maintained by Jeff Okamoto
+<okamoto@corp.hp.com>. It is now maintained as part of Perl itself.
With lots of help and suggestions from Dean Roehrich, Malcolm Beattie,
Andreas Koenig, Paul Hudson, Ilya Zakharevich, Paul Marquess, Neil
-Bowers, Matthew Green, Tim Bunce, Spider Boardman, and Ulrich Pfeifer.
-
-API Listing by Dean Roehrich <F<roehrich@cray.com>>.
-
-=head1 DATE
+Bowers, Matthew Green, Tim Bunce, Spider Boardman, Ulrich Pfeifer,
+Stephen McCamant, and Gurusamy Sarathy.
-Version 31.6: 1997/4/14
+API Listing originally by Dean Roehrich <roehrich@cray.com>.