#
# Tim.Bunce@ig.co.uk, August 1994
-$VERSION = "1.03"; # avoid typo warning
+$VERSION = "1.04"; # avoid typo warning
require AutoLoader;
*AUTOLOAD = \&AutoLoader::AUTOLOAD;
DynaLoader - Dynamically load C libraries into Perl code
-dl_error(), dl_findfile(), dl_expandspec(), dl_load_file(), dl_find_symbol(), dl_find_symbol_anywhere(), dl_undef_symbols(), dl_install_xsub(), dl_load_flags(), bootstrap() - routines used by DynaLoader modules
+dl_error(), dl_findfile(), dl_expandspec(), dl_load_file(), dl_unload_file(), dl_find_symbol(), dl_find_symbol_anywhere(), dl_undef_symbols(), dl_install_xsub(), dl_load_flags(), bootstrap() - routines used by DynaLoader modules
=head1 SYNOPSIS
$symref = dl_find_symbol_anywhere($symbol) Perl
$libref = dl_load_file($filename, $flags) C
+ $status = dl_unload_file($libref) C
$symref = dl_find_symbol($libref, $symbol) C
@symbols = dl_undef_symbols() C
dl_install_xsub($name, $symref [, $filename]) C
Linux, and is a common choice when providing a "wrapper" on other
mechanisms as is done in the OS/2 port.)
+=item dl_unload_file()
+
+Syntax:
+
+ $status = dl_unload_file($libref)
+
+Dynamically unload $libref, which must be an opaque 'library reference' as
+returned from dl_load_file. Returns one on success and zero on failure.
+
+This function is optional and may not necessarily be provided on all platforms.
+If it is defined, it is called automatically when the interpreter exits for
+every shared object or library loaded by DynaLoader::bootstrap. All such
+library references are stored in @dl_librefs by DynaLoader::Bootstrap as it
+loads the libraries. The files are unloaded in the reverse order in to they
+were initially loaded.
+
+This unloading is usually necessary when embedding a shared-object perl (e.g.
+one configured with -Duseshrplib) within a larger application, and the perl
+interpreter is created and destroyed several times within the lifetime of the
+application. In this case it is possible that the system dynamic linker will
+unload and then subsequently reload the shared libperl without relocating any
+references to it from any files DynaLoaded by the previous incarnation of the
+interpreter. As a result, any shared objects opened by DynaLoader may point to
+a now invalid 'ghost' of the libperl shared object, causing apparently random
+memory corruption and crashes. This behaviour is most commonly seen when using
+Apache and mod_perl built with the APXS mechanism.
+
+ SunOS: dlclose($libref)
+ HP-UX: ???
+ Linux: ???
+ NeXT: ???
+ VMS: ???
+
+(The dlclose() function is also used by Solaris and some versions of
+Linux, and is a common choice when providing a "wrapper" on other
+mechanisms as is done in the OS/2 port.)
+
=item dl_loadflags()
Syntax:
'XSLoader_pm.PL'=>'XSLoader.pm'},
PM => {'DynaLoader.pm' => '$(INST_LIBDIR)/DynaLoader.pm',
'XSLoader.pm' => '$(INST_LIBDIR)/XSLoader.pm'},
+ depend => {'DynaLoader.o' => 'dlutils.c'},
clean => {FILES => 'DynaLoader.c DynaLoader.xs DynaLoader.pm ' .
'XSLoader.pm'},
);
* Created: 10th July 1994
*
* Modified:
- * 15th July 1994 - Added code to explicitly save any error messages.
- * 3rd August 1994 - Upgraded to v3 spec.
- * 9th August 1994 - Changed to use IV
- * 10th August 1994 - Tim Bunce: Added RTLD_LAZY, switchable debugging,
- * basic FreeBSD support, removed ClearError
+ * 15th July 1994 - Added code to explicitly save any error messages.
+ * 3rd August 1994 - Upgraded to v3 spec.
+ * 9th August 1994 - Changed to use IV
+ * 10th August 1994 - Tim Bunce: Added RTLD_LAZY, switchable debugging,
+ * basic FreeBSD support, removed ClearError
+ * 29th Feburary 2000 - Alan Burlison: Added functionality to close dlopen'd
+ * files when the interpreter exits
*
*/
RTLD_LAZY (==2) on Solaris 2.
+ dlclose
+ -------
+ int
+ dlclose(handle)
+ void * handle;
+
+ This function takes the handle returned by a previous invocation of
+ dlopen and closes the associated dynamic object file. It returns zero
+ on success, and non-zero on failure.
+
+
dlsym
------
void *
Returns a null-terminated string which describes the last error
that occurred with either dlopen or dlsym. After each call to
dlerror the error message will be reset to a null pointer. The
- SaveError function is used to save the error as soo as it happens.
+ SaveError function is used to save the error as soon as it happens.
Return Types
sv_setiv( ST(0), PTR2IV(RETVAL));
}
+
+int
+dl_unload_file(libref)
+ void * libref
+ CODE:
+ DLDEBUG(1,PerlIO_printf(Perl_debug_log, "dl_unload_file(%lx):\n", libref));
+ if ((RETVAL = dlclose(libref) == 0 ? 1 : 0) == 0);
+ SaveError("%s", dlerror()) ;
+ DLDEBUG(2,PerlIO_printf(Perl_debug_log, " retval = %d\n", RETVAL));
+ OUTPUT:
+ RETVAL
+
+
void *
dl_find_symbol(libhandle, symbolname)
void * libhandle
* Currently this file is simply #included into dl_*.xs/.c files.
* It should really be split into a dlutils.h and dlutils.c
*
+ * Modified:
+ * 29th Feburary 2000 - Alan Burlison: Added functionality to close dlopen'd
+ * files when the interpreter exits
*/
#endif
+/* Close all dlopen'd files */
+static void
+dl_unload_all_files(pTHXo_ void *unused)
+{
+ CV *sub;
+ AV *dl_librefs;
+ SV *dl_libref;
+
+ if ((sub = get_cv("DynaLoader::dl_unload_file", FALSE)) != NULL) {
+ dl_librefs = get_av("DynaLoader::dl_librefs", FALSE);
+ while ((dl_libref = av_pop(dl_librefs)) != &PL_sv_undef) {
+ dSP;
+ ENTER;
+ SAVETMPS;
+ PUSHMARK(SP);
+ XPUSHs(sv_2mortal(dl_libref));
+ PUTBACK;
+ call_sv(sub, G_DISCARD);
+ FREETMPS;
+ LEAVE;
+ }
+ }
+}
+
+
static void
dl_generic_private_init(pTHXo) /* called by dl_*.xs dl_private_init() */
{
if (!dl_loaded_files)
dl_loaded_files = newHV(); /* provide cache for dl_*.xs if needed */
#endif
+ call_atexit(&dl_unload_all_files, (void*)0);
}
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