This function grants C<"SUPER"> token as a postfix of the stash name. The
GV returned from C<gv_fetchmeth> may be a method cache entry, which is not
-visible to Perl code. So when calling C<perl_call_sv>, you should not use
+visible to Perl code. So when calling C<call_sv>, 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.
These functions have the same side-effects and as C<gv_fetchmeth> with
C<level==0>. C<name> should be writable if contains C<':'> or C<'
''>. The warning against passing the GV returned by C<gv_fetchmeth> to
-C<perl_call_sv> apply equally to these functions.
+C<call_sv> apply equally to these functions.
=cut
*/
# converted to html commands.
#
-sub process_text1($$;$);
+sub process_text1($$;$$);
+sub pattern ($) { $_[0] ? '[^\S\n]+'.('>' x ($_[0] + 1)) : '>' }
+sub closing ($) { local($_) = shift; (defined && s/\s+$//) ? length : 0 }
sub process_text {
return if $ignore;
$$tref = $res;
}
-sub process_text1($$;$){
- my( $lev, $rstr, $func ) = @_;
+sub process_text1($$;$$){
+ my( $lev, $rstr, $func, $closing ) = @_;
$lev++ unless defined $func;
my $res = '';
} elsif( $func eq 'C' ){
# C<code> - can be a ref or <CODE></CODE>
# need to extract text
- my $par = go_ahead( $rstr, 'C' );
+ my $par = go_ahead( $rstr, 'C', $closing );
## clean-up of the link target
my $text = depod( $par );
## L<text|cross-ref> => produce text, use cross-ref for linking
## L<cross-ref> => make text from cross-ref
## need to extract text
- my $par = go_ahead( $rstr, 'L' );
+ my $par = go_ahead( $rstr, 'L', $closing );
# some L<>'s that shouldn't be:
# a) full-blown URL's are emitted as-is
unless $$rstr =~ s/^>//;
} else {
- while( $$rstr =~ s/\A(.*?)([BCEFILSXZ]<|>)//s ){
+ my $term = pattern $closing;
+ while( $$rstr =~ s/\A(.*?)(([BCEFILSXZ])<(<+[^\S\n]+)?|$term)//s ){
# all others: either recurse into new function or
- # terminate at closing angle bracket
+ # terminate at closing angle bracket(s)
my $pt = $1;
- $pt .= '>' if $2 eq '>' && $lev == 1;
+ $pt .= $2 if !$3 && $lev == 1;
$res .= $lev == 1 ? pure_text( $pt ) : inIS_text( $pt );
- return $res if $2 eq '>' && $lev > 1;
- if( $2 ne '>' ){
- $res .= process_text1( $lev, $rstr, substr($2,0,1) );
+ return $res if !$3 && $lev > 1;
+ if( $3 ){
+ $res .= process_text1( $lev, $rstr, $3, closing $4 );
}
}
#
# go_ahead: extract text of an IS (can be nested)
#
-sub go_ahead($$){
- my( $rstr, $func ) = @_;
+sub go_ahead($$$){
+ my( $rstr, $func, $closing ) = @_;
my $res = '';
- my $level = 1;
- while( $$rstr =~ s/\A(.*?)([BCEFILSXZ]<|>)//s ){
+ my @closing = ($closing);
+ while( $$rstr =~
+ s/\A(.*?)(([BCEFILSXZ])<(<+[^\S\n]+)?|@{[pattern $closing[0]]})//s ){
$res .= $1;
- if( $2 eq '>' ){
- return $res if --$level == 0;
+ unless( $3 ){
+ shift @closing;
+ return $res unless @closing;
} else {
- ++$level;
+ unshift @closing, closing $4;
}
$res .= $2;
}
$E2c{verbar} = '|';
$E2c{amp} = '&'; # in Tk's pods
-sub depod1($;$);
+sub depod1($;$$);
sub depod($){
my $string;
}
}
-sub depod1($;$){
- my( $rstr, $func ) = @_;
+sub depod1($;$$){
+ my( $rstr, $func, $closing ) = @_;
my $res = '';
return $res unless defined $$rstr;
if( ! defined( $func ) ){
# skip to next begin of an interior sequence
- while( $$rstr =~ s/\A(.*?)([BCEFILSXZ])<// ){
+ while( $$rstr =~ s/\A(.*?)([BCEFILSXZ])<(<+[^\S\n]+)?// ){
# recurse into its text
- $res .= $1 . depod1( $rstr, $2 );
+ $res .= $1 . depod1( $rstr, $2, closing $3);
}
$res .= $$rstr;
} elsif( $func eq 'E' ){
} else {
# all others: either recurse into new function or
# terminate at closing angle bracket
- while( $$rstr =~ s/\A(.*?)([BCEFILSXZ]<|>)// ){
+ my $term = pattern $closing;
+ while( $$rstr =~ s/\A(.*?)(([BCEFILSXZ])<(<+[^\S\n]+)?|$term)// ){
$res .= $1;
- last if $2 eq '>';
- $res .= depod1( $rstr, substr($2,0,1) );
+ last unless $3;
+ $res .= depod1( $rstr, $3, closing $4 );
}
## If we're here and $2 ne '>': undelimited interior sequence.
## Ignored, as this is called without proper indication of where we are.
double strut; /* alignment problems */
#endif
struct {
- u_char ovu_magic; /* magic number */
u_char ovu_index; /* bucket # */
+ u_char ovu_magic; /* magic number */
#ifdef RCHECK
u_short ovu_size; /* actual block size */
u_int ovu_rmagic; /* range magic number */
This function grants C<"SUPER"> token as a postfix of the stash name. The
GV returned from C<gv_fetchmeth> may be a method cache entry, which is not
-visible to Perl code. So when calling C<perl_call_sv>, you should not use
+visible to Perl code. So when calling C<call_sv>, 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.
These functions have the same side-effects and as C<gv_fetchmeth> with
C<level==0>. C<name> should be writable if contains C<':'> or C<'
''>. The warning against passing the GV returned by C<gv_fetchmeth> to
-C<perl_call_sv> apply equally to these functions.
+C<call_sv> apply equally to these functions.
GV* gv_fetchmethod_autoload(HV* stash, const char* name, I32 autoload)
it would be a good idea to have read the following two documents -
L<perlxs> and L<perlguts>.
-=head1 THE PERL_CALL FUNCTIONS
+=head1 THE CALL_ FUNCTIONS
Although this stuff is easier to explain using examples, you first need
be aware of a few important definitions.
Perl has a number of C functions that allow you to call Perl
subroutines. They are
- I32 perl_call_sv(SV* sv, I32 flags) ;
- I32 perl_call_pv(char *subname, I32 flags) ;
- I32 perl_call_method(char *methname, I32 flags) ;
- I32 perl_call_argv(char *subname, I32 flags, register char **argv) ;
+ I32 call_sv(SV* sv, I32 flags) ;
+ I32 call_pv(char *subname, I32 flags) ;
+ I32 call_method(char *methname, I32 flags) ;
+ I32 call_argv(char *subname, I32 flags, register char **argv) ;
-The key function is I<perl_call_sv>. All the other functions are
+The key function is I<call_sv>. All the other functions are
fairly simple wrappers which make it easier to call Perl subroutines in
-special cases. At the end of the day they will all call I<perl_call_sv>
+special cases. At the end of the day they will all call I<call_sv>
to invoke the Perl subroutine.
-All the I<perl_call_*> functions have a C<flags> parameter which is
+All the I<call_*> functions have a C<flags> parameter which is
used to pass a bit mask of options to Perl. This bit mask operates
identically for each of the functions. The settings available in the
bit mask are discussed in L<FLAG VALUES>.
=over 5
-=item perl_call_sv
+=item call_sv
-I<perl_call_sv> takes two parameters, the first, C<sv>, is an SV*.
+I<call_sv> takes two parameters, the first, C<sv>, is an SV*.
This allows you to specify the Perl subroutine to be called either as a
C string (which has first been converted to an SV) or a reference to a
-subroutine. The section, I<Using perl_call_sv>, shows how you can make
-use of I<perl_call_sv>.
+subroutine. The section, I<Using call_sv>, shows how you can make
+use of I<call_sv>.
-=item perl_call_pv
+=item call_pv
-The function, I<perl_call_pv>, is similar to I<perl_call_sv> except it
+The function, I<call_pv>, is similar to I<call_sv> except it
expects its first parameter to be a C char* which identifies the Perl
-subroutine you want to call, e.g., C<perl_call_pv("fred", 0)>. If the
+subroutine you want to call, e.g., C<call_pv("fred", 0)>. If the
subroutine you want to call is in another package, just include the
package name in the string, e.g., C<"pkg::fred">.
-=item perl_call_method
+=item call_method
-The function I<perl_call_method> is used to call a method from a Perl
+The function I<call_method> is used to call a method from a Perl
class. The parameter C<methname> corresponds to the name of the method
to be called. Note that the class that the method belongs to is passed
on the Perl stack rather than in the parameter list. This class can be
either the name of the class (for a static method) or a reference to an
object (for a virtual method). See L<perlobj> for more information on
-static and virtual methods and L<Using perl_call_method> for an example
-of using I<perl_call_method>.
+static and virtual methods and L<Using call_method> for an example
+of using I<call_method>.
-=item perl_call_argv
+=item call_argv
-I<perl_call_argv> calls the Perl subroutine specified by the C string
+I<call_argv> calls the Perl subroutine specified by the C string
stored in the C<subname> parameter. It also takes the usual C<flags>
parameter. The final parameter, C<argv>, consists of a NULL terminated
list of C strings to be passed as parameters to the Perl subroutine.
-See I<Using perl_call_argv>.
+See I<Using call_argv>.
=back
=head1 FLAG VALUES
-The C<flags> parameter in all the I<perl_call_*> functions is a bit mask
+The C<flags> parameter in all the I<call_*> functions is a bit mask
which can consist of any combination of the symbols defined below,
OR'ed together.
=back
-The value returned by the I<perl_call_*> function indicates how many
+The value returned by the I<call_*> function indicates how many
items have been returned by the Perl subroutine - in this case it will
be 0.
=head2 G_SCALAR
Calls the Perl subroutine in a scalar context. This is the default
-context flag setting for all the I<perl_call_*> functions.
+context flag setting for all the I<call_*> functions.
This flag has 2 effects:
=back
-The value returned by the I<perl_call_*> function indicates how many
+The value returned by the I<call_*> function indicates how many
items have been returned by the Perl subroutine - in this case it will
be either 0 or 1.
accessible from the stack - think of the case where only one value is
returned as being a list with only one element. Any other items that
were returned will not exist by the time control returns from the
-I<perl_call_*> function. The section I<Returning a list in a scalar
+I<call_*> function. The section I<Returning a list in a scalar
context> shows an example of this behavior.
=item 2.
It ensures that all items returned from the subroutine will be
-accessible when control returns from the I<perl_call_*> function.
+accessible when control returns from the I<call_*> function.
=back
-The value returned by the I<perl_call_*> function indicates how many
+The value returned by the I<call_*> function indicates how many
items have been returned by the Perl subroutine.
If 0, then you have specified the G_DISCARD flag.
=head2 G_DISCARD
-By default, the I<perl_call_*> functions place the items returned from
+By default, the I<call_*> functions place the items returned from
by the Perl subroutine on the stack. If you are not interested in
these items, then setting this flag will make Perl get rid of them
automatically for you. Note that it is still possible to indicate a
=head2 G_NOARGS
-Whenever a Perl subroutine is called using one of the I<perl_call_*>
+Whenever a Perl subroutine is called using one of the I<call_*>
functions, it is assumed by default that parameters are to be passed to
the subroutine. If you are not passing any parameters to the Perl
subroutine, you can save a bit of time by setting this flag. It has
In fact, what can happen is that the Perl subroutine you have called
can access the C<@_> array from a previous Perl subroutine. This will
-occur when the code that is executing the I<perl_call_*> function has
+occur when the code that is executing the I<call_*> function has
itself been called from another Perl subroutine. The code below
illustrates this
type of event, specify the G_EVAL flag. It will put an I<eval { }>
around the subroutine call.
-Whenever control returns from the I<perl_call_*> function you need to
+Whenever control returns from the I<call_*> function you need to
check the C<$@> variable as you would in a normal Perl script.
-The value returned from the I<perl_call_*> function is dependent on
+The value returned from the I<call_*> function is dependent on
what other flags have been specified and whether an error has
occurred. Here are all the different cases that can occur:
=item *
-If the I<perl_call_*> function returns normally, then the value
+If the I<call_*> function returns normally, then the value
returned is as specified in the previous sections.
=item *
append any new errors to any existing value of C<$@>.
The G_KEEPERR flag is meant to be used in conjunction with G_EVAL in
-I<perl_call_*> functions that are used to implement such code. This flag
+I<call_*> functions that are used to implement such code. This flag
has no effect when G_EVAL is not used.
When G_KEEPERR is used, any errors in the called code will be prefixed
=head1 KNOWN PROBLEMS
This section outlines all known problems that exist in the
-I<perl_call_*> functions.
+I<call_*> functions.
=over 5
Specifically, if the two flags are used when calling a subroutine and
that subroutine does not call I<die>, the value returned by
-I<perl_call_*> will be wrong.
+I<call_*> will be wrong.
=item 2.
-In Perl 5.000 and 5.001 there is a problem with using I<perl_call_*> if
+In Perl 5.000 and 5.001 there is a problem with using I<call_*> if
the Perl sub you are calling attempts to trap a I<die>.
The symptom of this problem is that the called Perl sub will continue
Call_fred()
CODE:
PUSHMARK(SP) ;
- perl_call_pv("fred", G_DISCARD|G_NOARGS) ;
+ call_pv("fred", G_DISCARD|G_NOARGS) ;
fprintf(stderr, "back in Call_fred\n") ;
When C<Call_fred> is executed it will print
string will not get printed.
To work around this problem, you can either upgrade to Perl 5.002 or
-higher, or use the G_EVAL flag with I<perl_call_*> as shown below
+higher, or use the G_EVAL flag with I<call_*> as shown below
void
Call_fred()
CODE:
PUSHMARK(SP) ;
- perl_call_pv("fred", G_EVAL|G_DISCARD|G_NOARGS) ;
+ call_pv("fred", G_EVAL|G_DISCARD|G_NOARGS) ;
fprintf(stderr, "back in Call_fred\n") ;
=back
to any changes made to Perl in the future.
Another point worth noting is that in the first series of examples I
-have made use of only the I<perl_call_pv> function. This has been done
+have made use of only the I<call_pv> function. This has been done
to keep the code simpler and ease you into the topic. Wherever
-possible, if the choice is between using I<perl_call_pv> and
-I<perl_call_sv>, you should always try to use I<perl_call_sv>. See
-I<Using perl_call_sv> for details.
+possible, if the choice is between using I<call_pv> and
+I<call_sv>, you should always try to use I<call_sv>. See
+I<Using call_sv> for details.
=head2 No Parameters, Nothing returned
dSP ;
PUSHMARK(SP) ;
- perl_call_pv("PrintUID", G_DISCARD|G_NOARGS) ;
+ call_pv("PrintUID", G_DISCARD|G_NOARGS) ;
}
Simple, eh.
We aren't interested in anything returned from I<PrintUID>, so
G_DISCARD is specified. Even if I<PrintUID> was changed to
return some value(s), having specified G_DISCARD will mean that they
-will be wiped by the time control returns from I<perl_call_pv>.
+will be wiped by the time control returns from I<call_pv>.
=item 4.
-As I<perl_call_pv> is being used, the Perl subroutine is specified as a
+As I<call_pv> is being used, the Perl subroutine is specified as a
C string. In this case the subroutine name has been 'hard-wired' into the
code.
=item 5.
Because we specified G_DISCARD, it is not necessary to check the value
-returned from I<perl_call_pv>. It will always be 0.
+returned from I<call_pv>. It will always be 0.
=back
XPUSHs(sv_2mortal(newSViv(b)));
PUTBACK ;
- perl_call_pv("LeftString", G_DISCARD);
+ call_pv("LeftString", G_DISCARD);
FREETMPS ;
LEAVE ;
stack pointer. Even if you aren't passing any parameters (like the
example shown in the section I<No Parameters, Nothing returned>) you
must still call the C<PUSHMARK> macro before you can call any of the
-I<perl_call_*> functions--Perl still needs to know that there are no
+I<call_*> functions--Perl still needs to know that there are no
parameters.
The C<PUTBACK> macro sets the global copy of the stack pointer to be
-the same as our local copy. If we didn't do this I<perl_call_pv>
+the same as our local copy. If we didn't do this I<call_pv>
wouldn't know where the two parameters we pushed were--remember that
up to now all the stack pointer manipulation we have done is with our
local copy, I<not> the global copy.
=item 7.
-Finally, I<LeftString> can now be called via the I<perl_call_pv>
+Finally, I<LeftString> can now be called via the I<call_pv>
function.
=back
XPUSHs(sv_2mortal(newSViv(b)));
PUTBACK ;
- count = perl_call_pv("Adder", G_SCALAR);
+ count = call_pv("Adder", G_SCALAR);
SPAGAIN ;
The only flag specified this time was G_SCALAR. That means the C<@_>
array will be created and that the value returned by I<Adder> will
-still exist after the call to I<perl_call_pv>.
+still exist after the call to I<call_pv>.
=item 2.
The purpose of the macro C<SPAGAIN> is to refresh the local copy of the
stack pointer. This is necessary because it is possible that the memory
allocated to the Perl stack has been reallocated whilst in the
-I<perl_call_pv> call.
+I<call_pv> call.
If you are making use of the Perl stack pointer in your code you must
always refresh the local copy using SPAGAIN whenever you make use
-of the I<perl_call_*> functions or any other Perl internal function.
+of the I<call_*> functions or any other Perl internal function.
=item 3.
Although only a single value was expected to be returned from I<Adder>,
-it is still good practice to check the return code from I<perl_call_pv>
+it is still good practice to check the return code from I<call_pv>
anyway.
Expecting a single value is not quite the same as knowing that there
XPUSHs(sv_2mortal(newSViv(b)));
PUTBACK ;
- count = perl_call_pv("AddSubtract", G_ARRAY);
+ count = call_pv("AddSubtract", G_ARRAY);
SPAGAIN ;
XPUSHs(sv_2mortal(newSViv(b)));
PUTBACK ;
- count = perl_call_pv("AddSubtract", G_SCALAR);
+ count = call_pv("AddSubtract", G_SCALAR);
SPAGAIN ;
XPUSHs(svb);
PUTBACK ;
- count = perl_call_pv("Inc", G_DISCARD);
+ count = call_pv("Inc", G_DISCARD);
if (count != 0)
croak ("call_Inc: expected 0 values from 'Inc', got %d\n",
}
To be able to access the two parameters that were pushed onto the stack
-after they return from I<perl_call_pv> it is necessary to make a note
+after they return from I<call_pv> it is necessary to make a note
of their addresses--thus the two variables C<sva> and C<svb>.
The reason this is necessary is that the area of the Perl stack which
held them will very likely have been overwritten by something else by
-the time control returns from I<perl_call_pv>.
+the time control returns from I<call_pv>.
XPUSHs(sv_2mortal(newSViv(b)));
PUTBACK ;
- count = perl_call_pv("Subtract", G_EVAL|G_SCALAR);
+ count = call_pv("Subtract", G_EVAL|G_SCALAR);
SPAGAIN ;
Note that the stack is popped using C<POPs> in the block where
C<SvTRUE(ERRSV)> is true. This is necessary because whenever a
-I<perl_call_*> function invoked with G_EVAL|G_SCALAR returns an error,
+I<call_*> function invoked with G_EVAL|G_SCALAR returns an error,
the top of the stack holds the value I<undef>. Because we want the
program to continue after detecting this error, it is essential that
the stack is tidied up by removing the I<undef>.
This example will fail to recognize that an error occurred inside the
C<eval {}>. Here's why: the call_Subtract code got executed while perl
was cleaning up temporaries when exiting the eval block, and because
-call_Subtract is implemented with I<perl_call_pv> using the G_EVAL
+call_Subtract is implemented with I<call_pv> using the G_EVAL
flag, it promptly reset C<$@>. This results in the failure of the
outermost test for C<$@>, and thereby the failure of the error trap.
-Appending the G_KEEPERR flag, so that the I<perl_call_pv> call in
+Appending the G_KEEPERR flag, so that the I<call_pv> call in
call_Subtract reads:
- count = perl_call_pv("Subtract", G_EVAL|G_SCALAR|G_KEEPERR);
+ count = call_pv("Subtract", G_EVAL|G_SCALAR|G_KEEPERR);
will preserve the error and restore reliable error handling.
-=head2 Using perl_call_sv
+=head2 Using call_sv
In all the previous examples I have 'hard-wired' the name of the Perl
subroutine to be called from C. Most of the time though, it is more
char * name
CODE:
PUSHMARK(SP) ;
- perl_call_pv(name, G_DISCARD|G_NOARGS) ;
+ call_pv(name, G_DISCARD|G_NOARGS) ;
That is fine as far as it goes. The thing is, the Perl subroutine
can be specified as only a string. For Perl 4 this was adequate,
but Perl 5 allows references to subroutines and anonymous subroutines.
-This is where I<perl_call_sv> is useful.
+This is where I<call_sv> is useful.
The code below for I<CallSubSV> is identical to I<CallSubPV> except
that the C<name> parameter is now defined as an SV* and we use
-I<perl_call_sv> instead of I<perl_call_pv>.
+I<call_sv> instead of I<call_pv>.
void
CallSubSV(name)
SV * name
CODE:
PUSHMARK(SP) ;
- perl_call_sv(name, G_DISCARD|G_NOARGS) ;
+ call_sv(name, G_DISCARD|G_NOARGS) ;
Because we are using an SV to call I<fred> the following can all be used
CallSubSV($ref) ;
CallSubSV( sub { print "Hello there\n" } ) ;
-As you can see, I<perl_call_sv> gives you much greater flexibility in
+As you can see, I<call_sv> gives you much greater flexibility in
how you can specify the Perl subroutine.
You should note that if it is necessary to store the SV (C<name> in the
CallSavedSub1()
CODE:
PUSHMARK(SP) ;
- perl_call_sv(rememberSub, G_DISCARD|G_NOARGS) ;
+ call_sv(rememberSub, G_DISCARD|G_NOARGS) ;
The reason this is wrong is that by the time you come to use the
pointer C<rememberSub> in C<CallSavedSub1>, it may or may not still refer
CallSavedSub2()
CODE:
PUSHMARK(SP) ;
- perl_call_sv(keepSub, G_DISCARD|G_NOARGS) ;
+ call_sv(keepSub, G_DISCARD|G_NOARGS) ;
To avoid creating a new SV every time C<SaveSub2> is called,
the function first checks to see if it has been called before. If not,
the existing SV, C<keepSub>, is overwritten with the new value using
C<SvSetSV>.
-=head2 Using perl_call_argv
+=head2 Using call_argv
Here is a Perl subroutine which prints whatever parameters are passed
to it.
foreach (@list) { print "$_\n" }
}
-and here is an example of I<perl_call_argv> which will call
+and here is an example of I<call_argv> which will call
I<PrintList>.
static char * words[] = {"alpha", "beta", "gamma", "delta", NULL} ;
{
dSP ;
- perl_call_argv("PrintList", G_DISCARD, words) ;
+ call_argv("PrintList", G_DISCARD, words) ;
}
Note that it is not necessary to call C<PUSHMARK> in this instance.
-This is because I<perl_call_argv> will do it for you.
+This is because I<call_argv> will do it for you.
-=head2 Using perl_call_method
+=head2 Using call_method
Consider the following Perl code
XPUSHs(sv_2mortal(newSViv(index))) ;
PUTBACK;
- perl_call_method(method, G_DISCARD) ;
+ call_method(method, G_DISCARD) ;
void
call_PrintID(class, method)
XPUSHs(sv_2mortal(newSVpv(class, 0))) ;
PUTBACK;
- perl_call_method(method, G_DISCARD) ;
+ call_method(method, G_DISCARD) ;
So the methods C<PrintID> and C<Display> can be invoked like this
The only thing to note is that in both the static and virtual methods,
the method name is not passed via the stack--it is used as the first
-parameter to I<perl_call_method>.
+parameter to I<call_method>.
=head2 Using GIMME_V
=head2 Using Perl to dispose of temporaries
In the examples given to date, any temporaries created in the callback
-(i.e., parameters passed on the stack to the I<perl_call_*> function or
+(i.e., parameters passed on the stack to the I<call_*> function or
values returned via the stack) have been freed by one of these methods
=over 5
=item *
-specifying the G_DISCARD flag with I<perl_call_*>.
+specifying the G_DISCARD flag with I<call_*>.
=item *
...
error occurs
...
- external library --> perl_call --> perl
+ external library --> call_* --> perl
|
- perl <-- XSUB <-- external library <-- perl_call <----+
+ perl <-- XSUB <-- external library <-- call_* <----+
-After processing of the error using I<perl_call_*> is completed,
+After processing of the error using I<call_*> is completed,
control reverts back to Perl more or less immediately.
In the diagram, the further right you go the more deeply nested the
perl --> XSUB --> event handler
...
- event handler --> perl_call --> perl
+ event handler --> call_* --> perl
|
- event handler <-- perl_call <----+
+ event handler <-- call_* <----+
...
- event handler --> perl_call --> perl
+ event handler --> call_* --> perl
|
- event handler <-- perl_call <----+
+ event handler <-- call_* <----+
...
- event handler --> perl_call --> perl
+ event handler --> call_* --> perl
|
- event handler <-- perl_call <----+
+ event handler <-- call_* <----+
In this case the flow of control can consist of only the repeated
sequence
- event handler --> perl_call --> perl
+ event handler --> call_* --> perl
for practically the complete duration of the program. This means that
control may I<never> drop back to the surrounding scope in Perl at the
PUSHMARK(SP) ;
/* Call the Perl sub to process the callback */
- perl_call_sv(callback, G_DISCARD) ;
+ call_sv(callback, G_DISCARD) ;
}
PUTBACK ;
/* Call the Perl sub */
- perl_call_sv(*sv, G_DISCARD) ;
+ call_sv(*sv, G_DISCARD) ;
}
For completeness, here is C<asynch_close>. This shows how to remove
PUTBACK ;
/* Call the Perl sub */
- perl_call_sv(Map[index].PerlSub, G_DISCARD) ;
+ call_sv(Map[index].PerlSub, G_DISCARD) ;
}
static void
XPUSHs(sv_2mortal(newSViv(b)));
PUTBACK ;
- count = perl_call_pv("AddSubtract", G_ARRAY);
+ count = call_pv("AddSubtract", G_ARRAY);
SPAGAIN ;
SP -= count ;
=head2 Creating and calling an anonymous subroutine in C
-As we've already shown, C<perl_call_sv> can be used to invoke an
+As we've already shown, C<call_sv> can be used to invoke an
anonymous subroutine. However, our example showed a Perl script
invoking an XSUB to perform this operation. Let's see how it can be
done inside our C code:
...
- SV *cvrv = perl_eval_pv("sub { print 'You will not find me cluttering any namespace!' }", TRUE);
+ SV *cvrv = eval_pv("sub { print 'You will not find me cluttering any namespace!' }", TRUE);
...
- perl_call_sv(cvrv, G_VOID|G_NOARGS);
+ call_sv(cvrv, G_VOID|G_NOARGS);
-C<perl_eval_pv> is used to compile the anonymous subroutine, which
-will be the return value as well (read more about C<perl_eval_pv> in
-L<perlguts/perl_eval_pv>). Once this code reference is in hand, it
+C<eval_pv> is used to compile the anonymous subroutine, which
+will be the return value as well (read more about C<eval_pv> in
+L<perlguts/eval_pv>). Once this code reference is in hand, it
can be mixed in with all the previous examples we've shown.
=head1 SEE ALSO
=item Callback called exit
-(F) A subroutine invoked from an external package via perl_call_sv()
+(F) A subroutine invoked from an external package via call_sv()
exited by calling exit.
=item Can't "goto" out of a pseudo block
=item B<Use C from Perl?>
-Read L<perlxstut>, L<perlxs>, L<h2xs>, and L<perlguts>.
+Read L<perlxstut>, L<perlxs>, L<h2xs>, L<perlguts>, and L<perlapi>.
=item B<Use a Unix program from Perl?>
=head2 Calling a Perl subroutine from your C program
-To call individual Perl subroutines, you can use any of the B<perl_call_*>
+To call individual Perl subroutines, you can use any of the B<call_*>
functions documented in L<perlcall>.
-In this example we'll use C<perl_call_argv>.
+In this example we'll use C<call_argv>.
That's shown below, in a program I'll call I<showtime.c>.
/*** skipping perl_run() ***/
- perl_call_argv("showtime", G_DISCARD | G_NOARGS, args);
+ call_argv("showtime", G_DISCARD | G_NOARGS, args);
perl_destruct(my_perl);
perl_free(my_perl);
If you want to pass arguments to the Perl subroutine, you can add
strings to the C<NULL>-terminated C<args> list passed to
-I<perl_call_argv>. For other data types, or to examine return values,
+I<call_argv>. For other data types, or to examine return values,
you'll need to manipulate the Perl stack. That's demonstrated in the
last section of this document: L<Fiddling with the Perl stack from
your C program>.
=head2 Evaluating a Perl statement from your C program
Perl provides two API functions to evaluate pieces of Perl code.
-These are L<perlguts/perl_eval_sv> and L<perlguts/perl_eval_pv>.
+These are L<perlapi/eval_sv> and L<perlapi/eval_pv>.
Arguably, these are the only routines you'll ever need to execute
snippets of Perl code from within your C program. Your code can be as
L<perlfunc/use>, L<perlfunc/require>, and L<perlfunc/do> to
include external Perl files.
-I<perl_eval_pv> lets us evaluate individual Perl strings, and then
+I<eval_pv> lets us evaluate individual Perl strings, and then
extract variables for coercion into C types. The following program,
I<string.c>, executes three Perl strings, extracting an C<int> from
the first, a C<float> from the second, and a C<char *> from the third.
perl_run(my_perl);
/** Treat $a as an integer **/
- perl_eval_pv("$a = 3; $a **= 2", TRUE);
- printf("a = %d\n", SvIV(perl_get_sv("a", FALSE)));
+ eval_pv("$a = 3; $a **= 2", TRUE);
+ printf("a = %d\n", SvIV(get_sv("a", FALSE)));
/** Treat $a as a float **/
- perl_eval_pv("$a = 3.14; $a **= 2", TRUE);
- printf("a = %f\n", SvNV(perl_get_sv("a", FALSE)));
+ eval_pv("$a = 3.14; $a **= 2", TRUE);
+ printf("a = %f\n", SvNV(get_sv("a", FALSE)));
/** Treat $a as a string **/
- perl_eval_pv("$a = 'rekcaH lreP rehtonA tsuJ'; $a = reverse($a);", TRUE);
- printf("a = %s\n", SvPV(perl_get_sv("a", FALSE), n_a));
+ eval_pv("$a = 'rekcaH lreP rehtonA tsuJ'; $a = reverse($a);", TRUE);
+ printf("a = %s\n", SvPV(get_sv("a", FALSE), n_a));
perl_destruct(my_perl);
perl_free(my_perl);
}
-All of those strange functions with I<sv> in their names help convert Perl scalars to C types. They're described in L<perlguts>.
+All of those strange functions with I<sv> in their names help convert Perl scalars to C types. They're described in L<perlguts> and L<perlapi>.
If you compile and run I<string.c>, you'll see the results of using
I<SvIV()> to create an C<int>, I<SvNV()> to create a C<float>, and
In the example above, we've created a global variable to temporarily
store the computed value of our eval'd expression. It is also
possible and in most cases a better strategy to fetch the return value
-from I<perl_eval_pv()> instead. Example:
+from I<eval_pv()> instead. Example:
...
STRLEN n_a;
- SV *val = perl_eval_pv("reverse 'rekcaH lreP rehtonA tsuJ'", TRUE);
+ SV *val = eval_pv("reverse 'rekcaH lreP rehtonA tsuJ'", TRUE);
printf("%s\n", SvPV(val,n_a));
...
=head2 Performing Perl pattern matches and substitutions from your C program
-The I<perl_eval_sv()> function lets us evaluate strings of Perl code, so we can
+The I<eval_sv()> function lets us evaluate strings of Perl code, so we can
define some functions that use it to "specialize" in matches and
substitutions: I<match()>, I<substitute()>, and I<matches()>.
#include <EXTERN.h>
#include <perl.h>
- /** my_perl_eval_sv(code, error_check)
- ** kinda like perl_eval_sv(),
+ /** my_eval_sv(code, error_check)
+ ** kinda like eval_sv(),
** but we pop the return value off the stack
**/
- SV* my_perl_eval_sv(SV *sv, I32 croak_on_error)
+ SV* my_eval_sv(SV *sv, I32 croak_on_error)
{
dSP;
SV* retval;
STRLEN n_a;
PUSHMARK(SP);
- perl_eval_sv(sv, G_SCALAR);
+ eval_sv(sv, G_SCALAR);
SPAGAIN;
retval = POPs;
sv_setpvf(command, "my $string = '%s'; $string =~ %s",
SvPV(string,n_a), pattern);
- retval = my_perl_eval_sv(command, TRUE);
+ retval = my_eval_sv(command, TRUE);
SvREFCNT_dec(command);
return SvIV(retval);
sv_setpvf(command, "$string = '%s'; ($string =~ %s)",
SvPV(*string,n_a), pattern);
- retval = my_perl_eval_sv(command, TRUE);
+ retval = my_eval_sv(command, TRUE);
SvREFCNT_dec(command);
- *string = perl_get_sv("string", FALSE);
+ *string = get_sv("string", FALSE);
return SvIV(retval);
}
sv_setpvf(command, "my $string = '%s'; @array = ($string =~ %s)",
SvPV(string,n_a), pattern);
- my_perl_eval_sv(command, TRUE);
+ my_eval_sv(command, TRUE);
SvREFCNT_dec(command);
- *match_list = perl_get_av("array", FALSE);
+ *match_list = get_av("array", FALSE);
num_matches = av_len(*match_list) + 1; /** assume $[ is 0 **/
return num_matches;
First you'll need to know how to convert between C types and Perl
types, with newSViv() and sv_setnv() and newAV() and all their
-friends. They're described in L<perlguts>.
+friends. They're described in L<perlguts> and L<perlapi>.
Then you'll need to know how to manipulate the Perl stack. That's
described in L<perlcall>.
XPUSHs(sv_2mortal(newSViv(a))); /* push the base onto the stack */
XPUSHs(sv_2mortal(newSViv(b))); /* push the exponent onto stack */
PUTBACK; /* make local stack pointer global */
- perl_call_pv("expo", G_SCALAR); /* call the function */
+ call_pv("expo", G_SCALAR); /* call the function */
SPAGAIN; /* refresh stack pointer */
/* pop the return value from stack */
printf ("%d to the %dth power is %d.\n", a, b, POPi);
the code into that package using L<perlfunc/eval>. In the example
below, each file will only be compiled once. Or, the application
might choose to clean out the symbol table associated with the file
-after it's no longer needed. Using L<perlcall/perl_call_argv>, We'll
+after it's no longer needed. Using L<perlapi/call_argv>, We'll
call the subroutine C<Embed::Persistent::eval_file> which lives in the
file C<persistent.pl> and pass the filename and boolean cleanup/cache
flag as arguments.
/* call the subroutine, passing it the filename as an argument */
args[0] = filename;
- perl_call_argv("Embed::Persistent::eval_file",
+ call_argv("Embed::Persistent::eval_file",
G_DISCARD | G_EVAL, args);
/* check $@ */
% cc -c interp.c `perl -MExtUtils::Embed -e ccopts`
% cc -o interp perlxsi.o interp.o `perl -MExtUtils::Embed -e ldopts`
-Consult L<perlxs> and L<perlguts> for more details.
+Consult L<perlxs>, L<perlguts>, and L<perlapi> for more details.
=head1 Embedding Perl under Win32
The C<-T> and C<-B> switches work as follows. The first block or so of the
file is examined for odd characters such as strange control codes or
-characters with the high bit set. If too many strange characters (E<gt>30%)
+characters with the high bit set. If too many strange characters (>30%)
are found, it's a C<-B> file, otherwise it's a C<-T> file. Also, any file
containing null in the first block is considered a binary file. If C<-T>
or C<-B> is used on a filehandle, the current stdio buffer is examined
Be aware that the optimizer might have optimized call frames away before
C<caller> had a chance to get the information. That means that C<caller(N)>
might not return information about the call frame you expect it do, for
-C<N E<gt> 1>. In particular, C<@DB::args> might have information from the
+C<< N > 1 >>. In particular, C<@DB::args> might have information from the
previous time C<caller> was called.
=item chdir EXPR
Outside an C<eval>, prints the value of LIST to C<STDERR> and
exits with the current value of C<$!> (errno). If C<$!> is C<0>,
-exits with the value of C<($? E<gt>E<gt> 8)> (backtick `command`
-status). If C<($? E<gt>E<gt> 8)> is C<0>, exits with C<255>. Inside
+exits with the value of C<<< ($? >> 8) >>> (backtick `command`
+status). If C<<< ($? >> 8) >>> is C<0>, exits with C<255>. Inside
an C<eval(),> the error message is stuffed into C<$@> and the
C<eval> is terminated with the undefined value. This makes
C<die> the way to raise an exception.
An C<eof> without an argument uses the last file read. Using C<eof()>
with empty parentheses is very different. It refers to the pseudo file
formed from the files listed on the command line and accessed via the
-C<E<lt>E<gt>> operator. Since C<E<lt>E<gt>> isn't explicitly opened,
-as a normal filehandle is, an C<eof()> before C<E<lt>E<gt>> has been
+C<< <> >> operator. Since C<< <> >> isn't explicitly opened,
+as a normal filehandle is, an C<eof()> before C<< <> >> has been
used will cause C<@ARGV> to be examined to determine if input is
available.
-In a C<while (E<lt>E<gt>)> loop, C<eof> or C<eof(ARGV)> can be used to
+In a C<< while (<>) >> loop, C<eof> or C<eof(ARGV)> can be used to
detect the end of each file, C<eof()> will only detect the end of the
last file. Examples:
Although the deepest nested array or hash will not spring into existence
just because its existence was tested, any intervening ones will.
-Thus C<$ref-E<gt>{"A"}> and C<$ref-E<gt>{"A"}-E<gt>{"B"}> will spring
+Thus C<< $ref->{"A"} >> and C<< $ref->{"A"}->{"B"} >> will spring
into existence due to the existence test for the $key element above.
This happens anywhere the arrow operator is used, including even:
Returns the value of EXPR with filename expansions such as the
standard Unix shell F</bin/csh> would do. This is the internal function
-implementing the C<E<lt>*.cE<gt>> operator, but you can use it directly.
-If EXPR is omitted, C<$_> is used. The C<E<lt>*.cE<gt>> operator is
+implementing the C<< <*.c> >> operator, but you can use it directly.
+If EXPR is omitted, C<$_> is used. The C<< <*.c> >> operator is
discussed in more detail in L<perlop/"I/O Operators">.
Beginning with v5.6.0, this operator is implemented using the standard
to get the correct function definitions. If F<ioctl.ph> doesn't
exist or doesn't have the correct definitions you'll have to roll your
-own, based on your C header files such as F<E<lt>sys/ioctl.hE<gt>>.
+own, based on your C header files such as F<< <sys/ioctl.h> >>.
(There is a Perl script called B<h2ph> that comes with the Perl kit that
may help you in this, but it's nontrivial.) SCALAR will be read and/or
written depending on the FUNCTION--a pointer to the string value of SCALAR
to open.) See L<perlopentut> for a kinder, gentler explanation of opening
files.
-If MODE is C<'E<lt>'> or nothing, the file is opened for input.
-If MODE is C<'E<gt>'>, the file is truncated and opened for
-output, being created if necessary. If MODE is C<'E<gt>E<gt>'>,
+If MODE is C<< '<' >> or nothing, the file is opened for input.
+If MODE is C<< '>' >>, the file is truncated and opened for
+output, being created if necessary. If MODE is C<<< '>>' >>>,
the file is opened for appending, again being created if necessary.
-You can put a C<'+'> in front of the C<'E<gt>'> or C<'E<lt>'> to indicate that
-you want both read and write access to the file; thus C<'+E<lt>'> is almost
-always preferred for read/write updates--the C<'+E<gt>'> mode would clobber the
+You can put a C<'+'> in front of the C<< '>' >> or C<< '<' >> to indicate that
+you want both read and write access to the file; thus C<< '+<' >> is almost
+always preferred for read/write updates--the C<< '+>' >> mode would clobber the
file first. You can't usually use either read-write mode for updating
textfiles, since they have variable length records. See the B<-i>
switch in L<perlrun> for a better approach. The file is created with
permissions of C<0666> modified by the process' C<umask> value.
-These various prefixes correspond to the fopen(3) modes of C<'r'>, C<'r+'>, C<'w'>,
-C<'w+'>, C<'a'>, and C<'a+'>.
+These various prefixes correspond to the fopen(3) modes of C<'r'>, C<'r+'>,
+C<'w'>, C<'w+'>, C<'a'>, and C<'a+'>.
In the 2-arguments (and 1-argument) form of the call the mode and
filename should be concatenated (in this order), possibly separated by
-spaces. It is possible to omit the mode if the mode is C<'E<lt>'>.
+spaces. It is possible to omit the mode if the mode is C<< '<' >>.
If the filename begins with C<'|'>, the filename is interpreted as a
command to which output is to be piped, and if the filename ends with a
and L<perlipc/"Bidirectional Communication"> for alternatives.)
In the 2-arguments (and 1-argument) form opening C<'-'> opens STDIN
-and opening C<'E<gt>-'> opens STDOUT.
+and opening C<< '>-' >> opens STDOUT.
Open returns
nonzero upon success, the undefined value otherwise. If the C<open>
}
You may also, in the Bourne shell tradition, specify an EXPR beginning
-with C<'E<gt>&'>, in which case the rest of the string is interpreted as the
+with C<< '>&' >>, in which case the rest of the string is interpreted as the
name of a filehandle (or file descriptor, if numeric) to be
-duped and opened. You may use C<&> after C<E<gt>>, C<E<gt>E<gt>>,
-C<E<lt>>, C<+E<gt>>, C<+E<gt>E<gt>>, and C<+E<lt>>. The
+duped and opened. You may use C<&> after C<< > >>, C<<< >> >>>,
+C<< < >>, C<< +> >>, C<<< +>> >>>, and C<< +< >>. The
mode you specify should match the mode of the original filehandle.
(Duping a filehandle does not take into account any existing contents of
stdio buffers.) Duping file handles is not yet supported for 3-argument
print STDOUT "stdout 2\n";
print STDERR "stderr 2\n";
-If you specify C<'E<lt>&=N'>, where C<N> is a number, then Perl will do an
+If you specify C<< '<&=N' >>, where C<N> is a number, then Perl will do an
equivalent of C's C<fdopen> of that file descriptor; this is more
parsimonious of file descriptors. For example:
because they obey the native byteorder and endianness. For example a
4-byte integer 0x12345678 (305419896 decimal) be ordered natively
(arranged in and handled by the CPU registers) into bytes as
-
+
0x12 0x34 0x56 0x78 # little-endian
0x78 0x56 0x34 0x12 # big-endian
-
+
Basically, the Intel, Alpha, and VAX CPUs are little-endian, while
everybody else, for example Motorola m68k/88k, PPC, Sparc, HP PA,
Power, and Cray are big-endian. MIPS can be either: Digital used it
the classic "Gulliver's Travels" (via the paper "On Holy Wars and a
Plea for Peace" by Danny Cohen, USC/ISI IEN 137, April 1, 1980) and
the egg-eating habits of the Lilliputians.
-
+
Some systems may have even weirder byte orders such as
-
+
0x56 0x78 0x12 0x34
0x34 0x12 0x78 0x56
-
+
You can see your system's preference with
print join(" ", map { sprintf "%#02x", $_ }
context (i.e. file slurp mode), and when an empty file is read, it
returns C<''> the first time, followed by C<undef> subsequently.
-This is the internal function implementing the C<E<lt>EXPRE<gt>>
-operator, but you can use it directly. The C<E<lt>EXPRE<gt>>
+This is the internal function implementing the C<< <EXPR> >>
+operator, but you can use it directly. The C<< <EXPR> >>
operator is discussed in more detail in L<perlop/"I/O Operators">.
$line = <STDIN>;
EOF on your read, and then sleep for a while, you might have to stick in a
seek() to reset things. The C<seek> doesn't change the current position,
but it I<does> clear the end-of-file condition on the handle, so that the
-next C<E<lt>FILEE<gt>> makes Perl try again to read something. We hope.
+next C<< <FILE> >> makes Perl try again to read something. We hope.
If that doesn't work (some stdios are particularly cantankerous), then
you may need something more like this:
select(undef, undef, undef, 0.25);
B<WARNING>: One should not attempt to mix buffered I/O (like C<read>
-or E<lt>FHE<gt>) with C<select>, except as permitted by POSIX, and even
+or <FH>) with C<select>, except as permitted by POSIX, and even
then only on POSIX systems. You have to use C<sysread> instead.
=item semctl ID,SEMNUM,CMD,ARG
is omitted, C<sort>s in standard string comparison order. If SUBNAME is
specified, it gives the name of a subroutine that returns an integer
less than, equal to, or greater than C<0>, depending on how the elements
-of the list are to be ordered. (The C<E<lt>=E<gt>> and C<cmp>
+of the list are to be ordered. (The C<< <=> >> and C<cmp>
operators are extremely useful in such routines.) SUBNAME may be a
scalar variable name (unsubscripted), in which case the value provides
the name of (or a reference to) the actual subroutine to use. In place
||
$a->[2] cmp $b->[2]
} map { [$_, /=(\d+)/, uc($_)] } @old;
-
+
# using a prototype allows you to use any comparison subroutine
# as a sort subroutine (including other package's subroutines)
package other;
ID, among other things. In versions of Perl prior to 5.004 the default
seed was just the current C<time>. This isn't a particularly good seed,
so many old programs supply their own seed value (often C<time ^ $$> or
-C<time ^ ($$ + ($$ E<lt>E<lt> 15))>), but that isn't necessary any more.
+C<time ^ ($$ + ($$ << 15))>), but that isn't necessary any more.
In fact, it's usually not necessary to call C<srand> at all, because if
it is not called explicitly, it is called implicitly at the first use of
S_IRWXU S_IRUSR S_IWUSR S_IXUSR
S_IRWXG S_IRGRP S_IWGRP S_IXGRP
S_IRWXO S_IROTH S_IWOTH S_IXOTH
-
+
# Setuid/Setgid/Stickiness.
S_ISUID S_ISGID S_ISVTX S_ISTXT
sub ordinal { unpack("c",$_[0]); } # same as ord()
In addition to fields allowed in pack(), you may prefix a field with
-a %E<lt>numberE<gt> to indicate that
-you want a E<lt>numberE<gt>-bit checksum of the items instead of the items
+a %<number> to indicate that
+you want a <number>-bit checksum of the items instead of the items
themselves. Default is a 16-bit checksum. Checksum is calculated by
summing numeric values of expanded values (for string fields the sum of
C<ord($char)> is taken, for bit fields the sum of zeroes and ones).
If you know the name of a scalar variable, you can get a pointer to its SV
by using the following:
- SV* perl_get_sv("package::varname", FALSE);
+ SV* get_sv("package::varname", FALSE);
This returns NULL if the variable does not exist.
If you know the name of an array variable, you can get a pointer to its AV
by using the following:
- AV* perl_get_av("package::varname", FALSE);
+ AV* get_av("package::varname", FALSE);
This returns NULL if the variable does not exist.
If you know the name of a hash variable, you can get a pointer to its HV
by using the following:
- HV* perl_get_hv("package::varname", FALSE);
+ HV* get_hv("package::varname", FALSE);
This returns NULL if the variable does not exist.
To create a new Perl variable with an undef value which can be accessed from
your Perl script, use the following routines, depending on the variable type.
- SV* perl_get_sv("package::varname", TRUE);
- AV* perl_get_av("package::varname", TRUE);
- HV* perl_get_hv("package::varname", TRUE);
+ SV* get_sv("package::varname", TRUE);
+ AV* get_av("package::varname", TRUE);
+ HV* get_hv("package::varname", TRUE);
Notice the use of TRUE as the second parameter. The new variable can now
be set, using the routines appropriate to the data type.
extern int dberror;
extern char *dberror_list;
- SV* sv = perl_get_sv("dberror", TRUE);
+ SV* sv = get_sv("dberror", TRUE);
sv_setiv(sv, (IV) dberror);
sv_setpv(sv, dberror_list[dberror]);
SvIOK_on(sv);
=head2 The Arrow Operator
-"C<-E<gt>>" is an infix dereference operator, just as it is in C
+"C<< -> >>" is an infix dereference operator, just as it is in C
and C++. If the right side is either a C<[...]>, C<{...}>, or a
C<(...)> subscript, then the left side must be either a hard or
symbolic reference to an array, a hash, or a subroutine respectively.
=head2 Relational Operators
-Binary "E<lt>" returns true if the left argument is numerically less than
+Binary "<" returns true if the left argument is numerically less than
the right argument.
-Binary "E<gt>" returns true if the left argument is numerically greater
+Binary ">" returns true if the left argument is numerically greater
than the right argument.
-Binary "E<lt>=" returns true if the left argument is numerically less than
+Binary "<=" returns true if the left argument is numerically less than
or equal to the right argument.
-Binary "E<gt>=" returns true if the left argument is numerically greater
+Binary ">=" returns true if the left argument is numerically greater
than or equal to the right argument.
Binary "lt" returns true if the left argument is stringwise less than
Binary "!=" returns true if the left argument is numerically not equal
to the right argument.
-Binary "E<lt>=E<gt>" returns -1, 0, or 1 depending on whether the left
+Binary "<=>" returns -1, 0, or 1 depending on whether the left
argument is numerically less than, equal to, or greater than the right
argument.
In list context, it's just the list argument separator, and inserts
both its arguments into the list.
-The =E<gt> digraph is mostly just a synonym for the comma operator. It's useful for
+The => digraph is mostly just a synonym for the comma operator. It's useful for
documenting arguments that come in pairs. As of release 5.001, it also forces
any word to the left of it to be interpreted as a string.
that
q{foo{bar}baz}
-
+
is the same as
'foo{bar}baz'
text is not evaluated as a command. If the
PATTERN is delimited by bracketing quotes, the REPLACEMENT has its own
pair of quotes, which may or may not be bracketing quotes, e.g.,
-C<s(foo)(bar)> or C<sE<lt>fooE<gt>/bar/>. A C</e> will cause the
+C<s(foo)(bar)> or C<< s<foo>/bar/ >>. A C</e> will cause the
replacement portion to be interpreted as a full-fledged Perl expression
and eval()ed right then and there. It is, however, syntax checked at
compile-time.
s/([^ ]*) *([^ ]*)/$2 $1/; # reverse 1st two fields
Note the use of $ instead of \ in the last example. Unlike
-B<sed>, we use the \E<lt>I<digit>E<gt> form in only the left hand side.
-Anywhere else it's $E<lt>I<digit>E<gt>.
+B<sed>, we use the \<I<digit>> form in only the left hand side.
+Anywhere else it's $<I<digit>>.
Occasionally, you can't use just a C</g> to get all the changes
to occur that you might want. Here are two common cases:
The first pass is finding the end of the quoted construct, whether
it be a multicharacter delimiter C<"\nEOF\n"> in the C<<<EOF>
construct, a C</> that terminates a C<qq//> construct, a C<]> which
-terminates C<qq[]> construct, or a C<E<gt>> which terminates a
-fileglob started with C<E<lt>>.
+terminates C<qq[]> construct, or a C<< > >> which terminates a
+fileglob started with C<< < >>.
When searching for single-character non-pairing delimiters, such
as C</>, combinations of C<\\> and C<\/> are skipped. However,
The only interpolation is removal of C<\> from pairs C<\\>.
-=item C<"">, C<``>, C<qq//>, C<qx//>, C<<file*globE<gt>>
+=item C<"">, C<``>, C<qq//>, C<qx//>, C<< <file*glob> >>
C<\Q>, C<\U>, C<\u>, C<\L>, C<\l> (possibly paired with C<\E>) are
converted to corresponding Perl constructs. Thus, C<"$foo\Qbaz$bar">
Note also that the interpolation code needs to make a decision on
where the interpolated scalar ends. For instance, whether
-C<"a $b -E<gt> {c}"> really means:
+C<< "a $b -> {c}" >> really means:
"a " . $b . " -> {c}";
while (($_ = <STDIN>) ne '0') { ... }
while (<STDIN>) { last unless $_; ... }
-In other boolean contexts, C<E<lt>I<filehandle>E<gt>> without an
+In other boolean contexts, C<< <I<filehandle>> >> without an
explicit C<defined> test or comparison elicit a warning if the B<-w>
command-line switch (the C<$^W> variable) is in effect.
the open() function, amongst others. See L<perlopentut> and
L<perlfunc/open> for details on this.
-If a E<lt>FILEHANDLEE<gt> is used in a context that is looking for
+If a <FILEHANDLE> is used in a context that is looking for
a list, a list comprising all input lines is returned, one line per
list element. It's easy to grow to a rather large data space this
way, so use with care.
-E<lt>FILEHANDLEE<gt> may also be spelled C<readline(*FILEHANDLE)>.
+<FILEHANDLE> may also be spelled C<readline(*FILEHANDLE)>.
See L<perlfunc/readline>.
-The null filehandle E<lt>E<gt> is special: it can be used to emulate the
-behavior of B<sed> and B<awk>. Input from E<lt>E<gt> comes either from
+The null filehandle <> is special: it can be used to emulate the
+behavior of B<sed> and B<awk>. Input from <> comes either from
standard input, or from each file listed on the command line. Here's
-how it works: the first time E<lt>E<gt> is evaluated, the @ARGV array is
+how it works: the first time <> is evaluated, the @ARGV array is
checked, and if it is empty, C<$ARGV[0]> is set to "-", which when opened
gives you standard input. The @ARGV array is then processed as a list
of filenames. The loop
except that it isn't so cumbersome to say, and will actually work.
It really does shift the @ARGV array and put the current filename
into the $ARGV variable. It also uses filehandle I<ARGV>
-internally--E<lt>E<gt> is just a synonym for E<lt>ARGVE<gt>, which
+internally--<> is just a synonym for <ARGV>, which
is magical. (The pseudo code above doesn't work because it treats
-E<lt>ARGVE<gt> as non-magical.)
+<ARGV> as non-magical.)
-You can modify @ARGV before the first E<lt>E<gt> as long as the array ends up
+You can modify @ARGV before the first <> as long as the array ends up
containing the list of filenames you really want. Line numbers (C<$.>)
continue as though the input were one big happy file. See the example
in L<perlfunc/eof> for how to reset line numbers on each file.
# ... # code for each line
}
-The E<lt>E<gt> symbol will return C<undef> for end-of-file only once.
+The <> symbol will return C<undef> for end-of-file only once.
If you call it again after this, it will assume you are processing another
@ARGV list, and if you haven't set @ARGV, will read input from STDIN.
If angle brackets contain is a simple scalar variable (e.g.,
-E<lt>$fooE<gt>), then that variable contains the name of the
+<$foo>), then that variable contains the name of the
filehandle to input from, or its typeglob, or a reference to the
same. For example:
reference, it is interpreted as a filename pattern to be globbed, and
either a list of filenames or the next filename in the list is returned,
depending on context. This distinction is determined on syntactic
-grounds alone. That means C<E<lt>$xE<gt>> is always a readline() from
-an indirect handle, but C<E<lt>$hash{key}E<gt>> is always a glob().
+grounds alone. That means C<< <$x> >> is always a readline() from
+an indirect handle, but C<< <$hash{key}> >> is always a glob().
That's because $x is a simple scalar variable, but C<$hash{key}> is
not--it's a hash element.
One level of double-quote interpretation is done first, but you can't
-say C<E<lt>$fooE<gt>> because that's an indirect filehandle as explained
+say C<< <$foo> >> because that's an indirect filehandle as explained
in the previous paragraph. (In older versions of Perl, programmers
would insert curly brackets to force interpretation as a filename glob:
-C<E<lt>${foo}E<gt>>. These days, it's considered cleaner to call the
+C<< <${foo}> >>. These days, it's considered cleaner to call the
internal function directly as C<glob($foo)>, which is probably the right
way to have done it in the first place.) For example:
projects / p5sagit/p5-mst-13.2.git / commitdiff