in the README.NOW file).
There exists a minor coexistence problem with dmake and Borland C++
-compilers. Namely, if a distribution have C files named with a mixed
+compilers. Namely, if a distribution has C files named with mixed
case letters, they will be compiled into appropriate .obj-files named
-with all lowercase letters, and every time when dmake will be invoked
+with all lowercase letters, and every time dmake is invoked
to bring files up to date, it will try to recompile such files again.
-For example, Tk distribution have a lot of such files, resulting in
-multiple recompiling everytime dmake is invoked. To avoid this, you
-may use the script "sncfnmcs.pl" after successful build. It is
-available in the win32 subdirectory.
+For example, Tk distribution has a lot of such files, resulting in
+needless recompiles everytime dmake is invoked. To avoid this, you
+may use the script "sncfnmcs.pl" after a successful build. It is
+available in the win32 subdirectory of the Perl source distribution.
=item Command Shell
ftp://ftp.xraylith.wisc.edu/pub/khan/gnu-win32/mingw32/
+You also need dmake. See L</"Make"> above on how to get it.
+
The GCC-2.95.2 bundle comes with Mingw32 libraries and headers.
Make sure you install the binaries that work with MSVCRT.DLL as indicated
in the README for the GCC bundle. You may need to set up a few environment
variables (usually ran from a batch file).
-The version of gcc-2.95.2-msvcrt.exe released 7 November 1999 left out
-a fix for certain command line quotes, so be sure to download and install
-fixes/quote-fix-msvcrt.exe too.
+There are a couple of problems with the version of gcc-2.95.2-msvcrt.exe
+released 7 November 1999:
-You also need dmake. See L</"Make"> above on how to get it.
+=over
+
+=item *
+
+It left out a fix for certain command line quotes. To fix this, be sure
+to download and install the file fixes/quote-fix-msvcrt.exe from the above
+ftp location.
+
+=item *
+
+The definition of the fpos_t type in stdio.h may be wrong. If your
+stdio.h has this problem, you will see an exception when running the
+test t/lib/io_xs.t. To fix this, change the typedef for fpos_t from
+"long" to "long long" in the file i386-mingw32msvc/include/stdio.h,
+and rebuild.
+
+=back
+
+A potentially simpler to install (but probably soon-to-be-outdated) bundle
+of the above package with the mentioned fixes already applied is available
+here:
+
+ http://downloads.ActiveState.com/pub/staff/gsar/gcc-2.95.2-msvcrt.zip
+ ftp://ftp.ActiveState.com/pub/staff/gsar/gcc-2.95.2-msvcrt.zip
=back
from where Borland chose to install it, into the Windows system directory
(usually somewhere like C:\WINNT\SYSTEM32) and rerun the test.
-If you're using Borland compiler versions 5.2 and below, you're risking
-to face a problem with finding incorrect header files. Don't be surprised
-when during compiling perl extension "Tk" you will fail because both perl
-and tk contain a header file with same name - "patchlevel.h". The latest
-Borland compilers are free of this misbehaviour, and they even invented
-option -VI- for backward (bugward) compatibility as "Use old Borland
-search algorithm to locate header files".
+If you're using Borland compiler versions 5.2 and below, you may run into
+problems finding the correct header files when building extensions. For
+example, building the "Tk" extension may fail because both perl and Tk
+contain a header file called "patchlevel.h". The latest Borland compiler
+(v5.5) is free of this misbehaviour, and it even supports an
+option -VI- for backward (bugward) compatibility for using the old Borland
+search algorithm to locate header files.
Please report any other failures as described under L<BUGS AND CAVEATS>.
Win9x support was added in 5.6 (Benjamin Stuhl).
-Last updated: 22 November 2000
+Last updated: 1 April 2001
=cut
Three macros control the major Perl build flavors: MULTIPLICITY,
USE_THREADS and PERL_OBJECT. The MULTIPLICITY build has a C structure
that packages all the interpreter state, there is a similar thread-specific
-data structure under USE_THREADS, and the PERL_OBJECT build has a C++
-class to maintain interpreter state. In all three cases,
+data structure under USE_THREADS, and the (now deprecated) PERL_OBJECT
+build has a C++ class to maintain interpreter state. In all three cases,
PERL_IMPLICIT_CONTEXT is also normally defined, and enables the
support for passing in a "hidden" first argument that represents all three
data structures.
details of the interpreter's context. THX stands for "thread", "this",
or "thingy", as the case may be. (And no, George Lucas is not involved. :-)
The first character could be 'p' for a B<p>rototype, 'a' for B<a>rgument,
-or 'd' for B<d>eclaration.
+or 'd' for B<d>eclaration, so we have C<pTHX>, C<aTHX> and C<dTHX>, and
+their variants.
-When Perl is built without PERL_IMPLICIT_CONTEXT, there is no first
-argument containing the interpreter's context. The trailing underscore
+When Perl is built without options that set PERL_IMPLICIT_CONTEXT, there is no
+first argument containing the interpreter's context. The trailing underscore
in the pTHX_ macro indicates that the macro expansion needs a comma
after the context argument because other arguments follow it. If
PERL_IMPLICIT_CONTEXT is not defined, pTHX_ will be ignored, and the
explicit arguments.
When a core function calls another, it must pass the context. This
-is normally hidden via macros. Consider C<sv_setsv>. It expands
+is normally hidden via macros. Consider C<sv_setsv>. It expands into
something like this:
ifdef PERL_IMPLICIT_CONTEXT
# see objXSUB.h
Under PERL_OBJECT in extensions (aka PERL_CAPI), or under
-MULTIPLICITY/USE_THREADS w/ PERL_IMPLICIT_CONTEXT in both core
-and extensions, it will be:
+MULTIPLICITY/USE_THREADS with PERL_IMPLICIT_CONTEXT in both core
+and extensions, it will become:
Perl_sv_setsv(aTHX_ foo, bar); # the canonical Perl "API"
# for all build flavors
Those are strictly for use within the core. Extensions and embedders
need only be aware of [pad]THX.
+=head2 So what happened to dTHR?
+
+C<dTHR> was introduced in perl 5.005 to support the older thread model.
+The older thread model now uses the C<THX> mechanism to pass context
+pointers around, so C<dTHR> is not useful any more. Perl 5.6.0 and
+later still have it for backward source compatibility, but it is defined
+to be a no-op.
+
=head2 How do I use all this in extensions?
When Perl is built with PERL_IMPLICIT_CONTEXT, extensions that call
macro with the underscore for functions that take explicit arguments,
or the form without the argument for functions with no explicit arguments.
+=head2 Should I do anything special if I call perl from multiple threads?
+
+If you create interpreters in one thread and then proceed to call them in
+another, you need to make sure perl's own Thread Local Storage (TLS) slot is
+initialized correctly in each of those threads.
+
+The C<perl_alloc> and C<perl_clone> API functions will automatically set
+the TLS slot to the interpreter they created, so that there is no need to do
+anything special if the interpreter is always accessed in the same thread that
+created it, and that thread did not create or call any other interpreters
+afterwards. If that is not the case, you have to set the TLS slot of the
+thread before calling any functions in the Perl API on that particular
+interpreter. This is done by calling the C<PERL_SET_CONTEXT> macro in that
+thread as the first thing you do:
+
+ /* do this before doing anything else with some_perl */
+ PERL_SET_CONTEXT(some_perl);
+
+ ... other Perl API calls on some_perl go here ...
+
=head2 Future Plans and PERL_IMPLICIT_SYS
Just as PERL_IMPLICIT_CONTEXT provides a way to bundle up everything
that the interpreter knows about itself and pass it around, so too are
there plans to allow the interpreter to bundle up everything it knows
about the environment it's running on. This is enabled with the
-PERL_IMPLICIT_SYS macro. Currently it only works with PERL_OBJECT,
-but is mostly there for MULTIPLICITY and USE_THREADS (see inside
-iperlsys.h).
+PERL_IMPLICIT_SYS macro. Currently it only works with PERL_OBJECT
+and USE_THREADS on Windows (see inside iperlsys.h).
This allows the ability to provide an extra pointer (called the "host"
environment) for all the system calls. This makes it possible for
=item s
-This is a static function and is defined as C<S_whatever>.
+This is a static function and is defined as C<S_whatever>, and usually
+called within the sources as C<whatever(...)>.
=item n
Afprd |void |croak |const char* pat|...
-=item m
+=item M
This function is part of the experimental development API, and may change
or disappear without notice.
projects / p5sagit/p5-mst-13.2.git / commitdiff