730 lines
24 KiB
Prolog
730 lines
24 KiB
Prolog
|
|
use Config;
|
|
|
|
sub to_string {
|
|
my ($value) = @_;
|
|
$value =~ s/\\/\\\\'/g;
|
|
$value =~ s/'/\\'/g;
|
|
return "'$value'";
|
|
}
|
|
|
|
unlink "DynaLoader.pm" if -f "DynaLoader.pm";
|
|
open OUT, ">DynaLoader.pm" or die $!;
|
|
print OUT <<'EOT';
|
|
|
|
# Generated from DynaLoader.pm.PL (resolved %Config::Config values)
|
|
|
|
package DynaLoader;
|
|
|
|
# And Gandalf said: 'Many folk like to know beforehand what is to
|
|
# be set on the table; but those who have laboured to prepare the
|
|
# feast like to keep their secret; for wonder makes the words of
|
|
# praise louder.'
|
|
|
|
# (Quote from Tolkien sugested by Anno Siegel.)
|
|
#
|
|
# See pod text at end of file for documentation.
|
|
# See also ext/DynaLoader/README in source tree for other information.
|
|
#
|
|
# Tim.Bunce@ig.co.uk, August 1994
|
|
|
|
$VERSION = $VERSION = "1.03"; # avoid typo warning
|
|
|
|
require AutoLoader;
|
|
*AUTOLOAD = \&AutoLoader::AUTOLOAD;
|
|
|
|
# The following require can't be removed during maintenance
|
|
# releases, sadly, because of the risk of buggy code that does
|
|
# require Carp; Carp::croak "..."; without brackets dying
|
|
# if Carp hasn't been loaded in earlier compile time. :-(
|
|
# We'll let those bugs get found on the development track.
|
|
require Carp if $] < 5.00450;
|
|
|
|
|
|
# enable debug/trace messages from DynaLoader perl code
|
|
$dl_debug = $ENV{PERL_DL_DEBUG} || 0 unless defined $dl_debug;
|
|
|
|
#
|
|
# Flags to alter dl_load_file behaviour. Assigned bits:
|
|
# 0x01 make symbols available for linking later dl_load_file's.
|
|
# (only known to work on Solaris 2 using dlopen(RTLD_GLOBAL))
|
|
# (ignored under VMS; effect is built-in to image linking)
|
|
#
|
|
# This is called as a class method $module->dl_load_flags. The
|
|
# definition here will be inherited and result on "default" loading
|
|
# behaviour unless a sub-class of DynaLoader defines its own version.
|
|
#
|
|
|
|
sub dl_load_flags { 0x00 }
|
|
|
|
# ($dl_dlext, $dlsrc)
|
|
# = @Config::Config{'dlext', 'dlsrc'};
|
|
EOT
|
|
|
|
print OUT " (\$dl_dlext, \$dlsrc) = (",
|
|
to_string($Config::Config{'dlext'}), ",",
|
|
to_string($Config::Config{'dlsrc'}), ")\n;" ;
|
|
|
|
print OUT <<'EOT';
|
|
|
|
# Some systems need special handling to expand file specifications
|
|
# (VMS support by Charles Bailey <bailey@HMIVAX.HUMGEN.UPENN.EDU>)
|
|
# See dl_expandspec() for more details. Should be harmless but
|
|
# inefficient to define on systems that don't need it.
|
|
$do_expand = $Is_VMS = $^O eq 'VMS';
|
|
|
|
@dl_require_symbols = (); # names of symbols we need
|
|
@dl_resolve_using = (); # names of files to link with
|
|
@dl_library_path = (); # path to look for files
|
|
@dl_librefs = (); # things we have loaded
|
|
@dl_modules = (); # Modules we have loaded
|
|
|
|
# This is a fix to support DLD's unfortunate desire to relink -lc
|
|
@dl_resolve_using = dl_findfile('-lc') if $dlsrc eq "dl_dld.xs";
|
|
|
|
# Initialise @dl_library_path with the 'standard' library path
|
|
# for this platform as determined by Configure
|
|
|
|
# push(@dl_library_path, split(' ', $Config::Config{'libpth'});
|
|
EOT
|
|
|
|
print OUT "push(\@dl_library_path, split(' ', ",
|
|
to_string($Config::Config{'libpth'}), "));\n";
|
|
|
|
print OUT <<'EOT';
|
|
|
|
# Add to @dl_library_path any extra directories we can gather from
|
|
# environment variables. So far LD_LIBRARY_PATH is the only known
|
|
# variable used for this purpose. Others may be added later.
|
|
push(@dl_library_path, split(/:/, $ENV{LD_LIBRARY_PATH}))
|
|
if $ENV{LD_LIBRARY_PATH};
|
|
|
|
|
|
# No prizes for guessing why we don't say 'bootstrap DynaLoader;' here.
|
|
boot_DynaLoader('DynaLoader') if defined(&boot_DynaLoader);
|
|
|
|
|
|
if ($dl_debug) {
|
|
print STDERR "DynaLoader.pm loaded (@INC, @dl_library_path)\n";
|
|
print STDERR "DynaLoader not linked into this perl\n"
|
|
unless defined(&boot_DynaLoader);
|
|
}
|
|
|
|
1; # End of main code
|
|
|
|
|
|
sub croak { require Carp; Carp::croak(@_) }
|
|
|
|
# The bootstrap function cannot be autoloaded (without complications)
|
|
# so we define it here:
|
|
|
|
sub bootstrap {
|
|
# use local vars to enable $module.bs script to edit values
|
|
local(@args) = @_;
|
|
local($module) = $args[0];
|
|
local(@dirs, $file);
|
|
|
|
unless ($module) {
|
|
require Carp;
|
|
Carp::confess("Usage: DynaLoader::bootstrap(module)");
|
|
}
|
|
|
|
# A common error on platforms which don't support dynamic loading.
|
|
# Since it's fatal and potentially confusing we give a detailed message.
|
|
croak("Can't load module $module, dynamic loading not available in this perl.\n".
|
|
" (You may need to build a new perl executable which either supports\n".
|
|
" dynamic loading or has the $module module statically linked into it.)\n")
|
|
unless defined(&dl_load_file);
|
|
|
|
my @modparts = split(/::/,$module);
|
|
my $modfname = $modparts[-1];
|
|
|
|
# Some systems have restrictions on files names for DLL's etc.
|
|
# mod2fname returns appropriate file base name (typically truncated)
|
|
# It may also edit @modparts if required.
|
|
$modfname = &mod2fname(\@modparts) if defined &mod2fname;
|
|
|
|
my $modpname = join('/',@modparts);
|
|
|
|
print STDERR "DynaLoader::bootstrap for $module ",
|
|
"(auto/$modpname/$modfname.$dl_dlext)\n" if $dl_debug;
|
|
|
|
foreach (@INC) {
|
|
chop($_ = VMS::Filespec::unixpath($_)) if $Is_VMS;
|
|
my $dir = "$_/auto/$modpname";
|
|
next unless -d $dir; # skip over uninteresting directories
|
|
|
|
# check for common cases to avoid autoload of dl_findfile
|
|
my $try = "$dir/$modfname.$dl_dlext";
|
|
last if $file = ($do_expand) ? dl_expandspec($try) : (-f $try && $try);
|
|
|
|
# no luck here, save dir for possible later dl_findfile search
|
|
push @dirs, $dir;
|
|
}
|
|
# last resort, let dl_findfile have a go in all known locations
|
|
$file = dl_findfile(map("-L$_",@dirs,@INC), $modfname) unless $file;
|
|
|
|
croak("Can't locate loadable object for module $module in \@INC (\@INC contains: @INC)")
|
|
unless $file; # wording similar to error from 'require'
|
|
|
|
my $bootname = "boot_$module";
|
|
$bootname =~ s/\W/_/g;
|
|
@dl_require_symbols = ($bootname);
|
|
|
|
# Execute optional '.bootstrap' perl script for this module.
|
|
# The .bs file can be used to configure @dl_resolve_using etc to
|
|
# match the needs of the individual module on this architecture.
|
|
my $bs = $file;
|
|
$bs =~ s/(\.\w+)?$/\.bs/; # look for .bs 'beside' the library
|
|
if (-s $bs) { # only read file if it's not empty
|
|
print STDERR "BS: $bs ($^O, $dlsrc)\n" if $dl_debug;
|
|
eval { do $bs; };
|
|
warn "$bs: $@\n" if $@;
|
|
}
|
|
|
|
# Many dynamic extension loading problems will appear to come from
|
|
# this section of code: XYZ failed at line 123 of DynaLoader.pm.
|
|
# Often these errors are actually occurring in the initialisation
|
|
# C code of the extension XS file. Perl reports the error as being
|
|
# in this perl code simply because this was the last perl code
|
|
# it executed.
|
|
|
|
my $libref = dl_load_file($file, $module->dl_load_flags) or
|
|
croak("Can't load '$file' for module $module: ".dl_error()."\n");
|
|
|
|
push(@dl_librefs,$libref); # record loaded object
|
|
|
|
my @unresolved = dl_undef_symbols();
|
|
if (@unresolved) {
|
|
require Carp;
|
|
Carp::carp("Undefined symbols present after loading $file: @unresolved\n");
|
|
}
|
|
|
|
my $boot_symbol_ref = dl_find_symbol($libref, $bootname) or
|
|
croak("Can't find '$bootname' symbol in $file\n");
|
|
|
|
my $xs = dl_install_xsub("${module}::bootstrap", $boot_symbol_ref, $file);
|
|
|
|
push(@dl_modules, $module); # record loaded module
|
|
|
|
# See comment block above
|
|
&$xs(@args);
|
|
}
|
|
|
|
|
|
#sub _check_file { # private utility to handle dl_expandspec vs -f tests
|
|
# my($file) = @_;
|
|
# return $file if (!$do_expand && -f $file); # the common case
|
|
# return $file if ( $do_expand && ($file=dl_expandspec($file)));
|
|
# return undef;
|
|
#}
|
|
|
|
|
|
# Let autosplit and the autoloader deal with these functions:
|
|
__END__
|
|
|
|
|
|
sub dl_findfile {
|
|
# Read ext/DynaLoader/DynaLoader.doc for detailed information.
|
|
# This function does not automatically consider the architecture
|
|
# or the perl library auto directories.
|
|
my (@args) = @_;
|
|
my (@dirs, $dir); # which directories to search
|
|
my (@found); # full paths to real files we have found
|
|
EOT
|
|
|
|
print OUT ' my $dl_ext= ' . to_string($Config::Config{'dlext'}) .
|
|
"; # \$Config::Config{'dlext'} suffix for perl extensions\n";
|
|
print OUT ' my $dl_so = ' . to_string($Config::Config{'so'}) .
|
|
"; # \$Config::Config{'so'} suffix for shared libraries\n";
|
|
|
|
print OUT <<'EOT';
|
|
|
|
print STDERR "dl_findfile(@args)\n" if $dl_debug;
|
|
|
|
# accumulate directories but process files as they appear
|
|
arg: foreach(@args) {
|
|
# Special fast case: full filepath requires no search
|
|
if ($Is_VMS && m%[:>/\]]% && -f $_) {
|
|
push(@found,dl_expandspec(VMS::Filespec::vmsify($_)));
|
|
last arg unless wantarray;
|
|
next;
|
|
}
|
|
elsif (m:/: && -f $_ && !$do_expand) {
|
|
push(@found,$_);
|
|
last arg unless wantarray;
|
|
next;
|
|
}
|
|
|
|
# Deal with directories first:
|
|
# Using a -L prefix is the preferred option (faster and more robust)
|
|
if (m:^-L:) { s/^-L//; push(@dirs, $_); next; }
|
|
|
|
# Otherwise we try to try to spot directories by a heuristic
|
|
# (this is a more complicated issue than it first appears)
|
|
if (m:/: && -d $_) { push(@dirs, $_); next; }
|
|
|
|
# VMS: we may be using native VMS directry syntax instead of
|
|
# Unix emulation, so check this as well
|
|
if ($Is_VMS && /[:>\]]/ && -d $_) { push(@dirs, $_); next; }
|
|
|
|
# Only files should get this far...
|
|
my(@names, $name); # what filenames to look for
|
|
if (m:-l: ) { # convert -lname to appropriate library name
|
|
s/-l//;
|
|
push(@names,"lib$_.$dl_so");
|
|
push(@names,"lib$_.a");
|
|
} else { # Umm, a bare name. Try various alternatives:
|
|
# these should be ordered with the most likely first
|
|
push(@names,"$_.$dl_ext") unless m/\.$dl_ext$/o;
|
|
push(@names,"$_.$dl_so") unless m/\.$dl_so$/o;
|
|
push(@names,"lib$_.$dl_so") unless m:/:;
|
|
push(@names,"$_.a") if !m/\.a$/ and $dlsrc eq "dl_dld.xs";
|
|
push(@names, $_);
|
|
}
|
|
foreach $dir (@dirs, @dl_library_path) {
|
|
next unless -d $dir;
|
|
chop($dir = VMS::Filespec::unixpath($dir)) if $Is_VMS;
|
|
foreach $name (@names) {
|
|
my($file) = "$dir/$name";
|
|
print STDERR " checking in $dir for $name\n" if $dl_debug;
|
|
$file = ($do_expand) ? dl_expandspec($file) : (-f $file && $file);
|
|
#$file = _check_file($file);
|
|
if ($file) {
|
|
push(@found, $file);
|
|
next arg; # no need to look any further
|
|
}
|
|
}
|
|
}
|
|
}
|
|
if ($dl_debug) {
|
|
foreach(@dirs) {
|
|
print STDERR " dl_findfile ignored non-existent directory: $_\n" unless -d $_;
|
|
}
|
|
print STDERR "dl_findfile found: @found\n";
|
|
}
|
|
return $found[0] unless wantarray;
|
|
@found;
|
|
}
|
|
|
|
|
|
sub dl_expandspec {
|
|
my($spec) = @_;
|
|
# Optional function invoked if DynaLoader.pm sets $do_expand.
|
|
# Most systems do not require or use this function.
|
|
# Some systems may implement it in the dl_*.xs file in which case
|
|
# this autoload version will not be called but is harmless.
|
|
|
|
# This function is designed to deal with systems which treat some
|
|
# 'filenames' in a special way. For example VMS 'Logical Names'
|
|
# (something like unix environment variables - but different).
|
|
# This function should recognise such names and expand them into
|
|
# full file paths.
|
|
# Must return undef if $spec is invalid or file does not exist.
|
|
|
|
my $file = $spec; # default output to input
|
|
|
|
if ($Is_VMS) { # dl_expandspec should be defined in dl_vms.xs
|
|
require Carp;
|
|
Carp::croak("dl_expandspec: should be defined in XS file!\n");
|
|
} else {
|
|
return undef unless -f $file;
|
|
}
|
|
print STDERR "dl_expandspec($spec) => $file\n" if $dl_debug;
|
|
$file;
|
|
}
|
|
|
|
sub dl_find_symbol_anywhere
|
|
{
|
|
my $sym = shift;
|
|
my $libref;
|
|
foreach $libref (@dl_librefs) {
|
|
my $symref = dl_find_symbol($libref,$sym);
|
|
return $symref if $symref;
|
|
}
|
|
return undef;
|
|
}
|
|
|
|
=head1 NAME
|
|
|
|
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
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
package YourPackage;
|
|
require DynaLoader;
|
|
@ISA = qw(... DynaLoader ...);
|
|
bootstrap YourPackage;
|
|
|
|
# optional method for 'global' loading
|
|
sub dl_load_flags { 0x01 }
|
|
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
This document defines a standard generic interface to the dynamic
|
|
linking mechanisms available on many platforms. Its primary purpose is
|
|
to implement automatic dynamic loading of Perl modules.
|
|
|
|
This document serves as both a specification for anyone wishing to
|
|
implement the DynaLoader for a new platform and as a guide for
|
|
anyone wishing to use the DynaLoader directly in an application.
|
|
|
|
The DynaLoader is designed to be a very simple high-level
|
|
interface that is sufficiently general to cover the requirements
|
|
of SunOS, HP-UX, NeXT, Linux, VMS and other platforms.
|
|
|
|
It is also hoped that the interface will cover the needs of OS/2, NT
|
|
etc and also allow pseudo-dynamic linking (using C<ld -A> at runtime).
|
|
|
|
It must be stressed that the DynaLoader, by itself, is practically
|
|
useless for accessing non-Perl libraries because it provides almost no
|
|
Perl-to-C 'glue'. There is, for example, no mechanism for calling a C
|
|
library function or supplying arguments. A C::DynaLib module
|
|
is available from CPAN sites which performs that function for some
|
|
common system types.
|
|
|
|
DynaLoader Interface Summary
|
|
|
|
@dl_library_path
|
|
@dl_resolve_using
|
|
@dl_require_symbols
|
|
$dl_debug
|
|
@dl_librefs
|
|
@dl_modules
|
|
Implemented in:
|
|
bootstrap($modulename) Perl
|
|
@filepaths = dl_findfile(@names) Perl
|
|
$flags = $modulename->dl_load_flags Perl
|
|
$symref = dl_find_symbol_anywhere($symbol) Perl
|
|
|
|
$libref = dl_load_file($filename, $flags) C
|
|
$symref = dl_find_symbol($libref, $symbol) C
|
|
@symbols = dl_undef_symbols() C
|
|
dl_install_xsub($name, $symref [, $filename]) C
|
|
$message = dl_error C
|
|
|
|
=over 4
|
|
|
|
=item @dl_library_path
|
|
|
|
The standard/default list of directories in which dl_findfile() will
|
|
search for libraries etc. Directories are searched in order:
|
|
$dl_library_path[0], [1], ... etc
|
|
|
|
@dl_library_path is initialised to hold the list of 'normal' directories
|
|
(F</usr/lib>, etc) determined by B<Configure> (C<$Config{'libpth'}>). This should
|
|
ensure portability across a wide range of platforms.
|
|
|
|
@dl_library_path should also be initialised with any other directories
|
|
that can be determined from the environment at runtime (such as
|
|
LD_LIBRARY_PATH for SunOS).
|
|
|
|
After initialisation @dl_library_path can be manipulated by an
|
|
application using push and unshift before calling dl_findfile().
|
|
Unshift can be used to add directories to the front of the search order
|
|
either to save search time or to override libraries with the same name
|
|
in the 'normal' directories.
|
|
|
|
The load function that dl_load_file() calls may require an absolute
|
|
pathname. The dl_findfile() function and @dl_library_path can be
|
|
used to search for and return the absolute pathname for the
|
|
library/object that you wish to load.
|
|
|
|
=item @dl_resolve_using
|
|
|
|
A list of additional libraries or other shared objects which can be
|
|
used to resolve any undefined symbols that might be generated by a
|
|
later call to load_file().
|
|
|
|
This is only required on some platforms which do not handle dependent
|
|
libraries automatically. For example the Socket Perl extension
|
|
library (F<auto/Socket/Socket.so>) contains references to many socket
|
|
functions which need to be resolved when it's loaded. Most platforms
|
|
will automatically know where to find the 'dependent' library (e.g.,
|
|
F</usr/lib/libsocket.so>). A few platforms need to be told the
|
|
location of the dependent library explicitly. Use @dl_resolve_using
|
|
for this.
|
|
|
|
Example usage:
|
|
|
|
@dl_resolve_using = dl_findfile('-lsocket');
|
|
|
|
=item @dl_require_symbols
|
|
|
|
A list of one or more symbol names that are in the library/object file
|
|
to be dynamically loaded. This is only required on some platforms.
|
|
|
|
=item @dl_librefs
|
|
|
|
An array of the handles returned by successful calls to dl_load_file(),
|
|
made by bootstrap, in the order in which they were loaded.
|
|
Can be used with dl_find_symbol() to look for a symbol in any of
|
|
the loaded files.
|
|
|
|
=item @dl_modules
|
|
|
|
An array of module (package) names that have been bootstrap'ed.
|
|
|
|
=item dl_error()
|
|
|
|
Syntax:
|
|
|
|
$message = dl_error();
|
|
|
|
Error message text from the last failed DynaLoader function. Note
|
|
that, similar to errno in unix, a successful function call does not
|
|
reset this message.
|
|
|
|
Implementations should detect the error as soon as it occurs in any of
|
|
the other functions and save the corresponding message for later
|
|
retrieval. This will avoid problems on some platforms (such as SunOS)
|
|
where the error message is very temporary (e.g., dlerror()).
|
|
|
|
=item $dl_debug
|
|
|
|
Internal debugging messages are enabled when $dl_debug is set true.
|
|
Currently setting $dl_debug only affects the Perl side of the
|
|
DynaLoader. These messages should help an application developer to
|
|
resolve any DynaLoader usage problems.
|
|
|
|
$dl_debug is set to C<$ENV{'PERL_DL_DEBUG'}> if defined.
|
|
|
|
For the DynaLoader developer/porter there is a similar debugging
|
|
variable added to the C code (see dlutils.c) and enabled if Perl was
|
|
built with the B<-DDEBUGGING> flag. This can also be set via the
|
|
PERL_DL_DEBUG environment variable. Set to 1 for minimal information or
|
|
higher for more.
|
|
|
|
=item dl_findfile()
|
|
|
|
Syntax:
|
|
|
|
@filepaths = dl_findfile(@names)
|
|
|
|
Determine the full paths (including file suffix) of one or more
|
|
loadable files given their generic names and optionally one or more
|
|
directories. Searches directories in @dl_library_path by default and
|
|
returns an empty list if no files were found.
|
|
|
|
Names can be specified in a variety of platform independent forms. Any
|
|
names in the form B<-lname> are converted into F<libname.*>, where F<.*> is
|
|
an appropriate suffix for the platform.
|
|
|
|
If a name does not already have a suitable prefix and/or suffix then
|
|
the corresponding file will be searched for by trying combinations of
|
|
prefix and suffix appropriate to the platform: "$name.o", "lib$name.*"
|
|
and "$name".
|
|
|
|
If any directories are included in @names they are searched before
|
|
@dl_library_path. Directories may be specified as B<-Ldir>. Any other
|
|
names are treated as filenames to be searched for.
|
|
|
|
Using arguments of the form C<-Ldir> and C<-lname> is recommended.
|
|
|
|
Example:
|
|
|
|
@dl_resolve_using = dl_findfile(qw(-L/usr/5lib -lposix));
|
|
|
|
|
|
=item dl_expandspec()
|
|
|
|
Syntax:
|
|
|
|
$filepath = dl_expandspec($spec)
|
|
|
|
Some unusual systems, such as VMS, require special filename handling in
|
|
order to deal with symbolic names for files (i.e., VMS's Logical Names).
|
|
|
|
To support these systems a dl_expandspec() function can be implemented
|
|
either in the F<dl_*.xs> file or code can be added to the autoloadable
|
|
dl_expandspec() function in F<DynaLoader.pm>. See F<DynaLoader.pm> for
|
|
more information.
|
|
|
|
=item dl_load_file()
|
|
|
|
Syntax:
|
|
|
|
$libref = dl_load_file($filename, $flags)
|
|
|
|
Dynamically load $filename, which must be the path to a shared object
|
|
or library. An opaque 'library reference' is returned as a handle for
|
|
the loaded object. Returns undef on error.
|
|
|
|
The $flags argument to alters dl_load_file behaviour.
|
|
Assigned bits:
|
|
|
|
0x01 make symbols available for linking later dl_load_file's.
|
|
(only known to work on Solaris 2 using dlopen(RTLD_GLOBAL))
|
|
(ignored under VMS; this is a normal part of image linking)
|
|
|
|
(On systems that provide a handle for the loaded object such as SunOS
|
|
and HPUX, $libref will be that handle. On other systems $libref will
|
|
typically be $filename or a pointer to a buffer containing $filename.
|
|
The application should not examine or alter $libref in any way.)
|
|
|
|
This is the function that does the real work. It should use the
|
|
current values of @dl_require_symbols and @dl_resolve_using if required.
|
|
|
|
SunOS: dlopen($filename)
|
|
HP-UX: shl_load($filename)
|
|
Linux: dld_create_reference(@dl_require_symbols); dld_link($filename)
|
|
NeXT: rld_load($filename, @dl_resolve_using)
|
|
VMS: lib$find_image_symbol($filename,$dl_require_symbols[0])
|
|
|
|
(The dlopen() 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:
|
|
|
|
$flags = dl_loadflags $modulename;
|
|
|
|
Designed to be a method call, and to be overridden by a derived class
|
|
(i.e. a class which has DynaLoader in its @ISA). The definition in
|
|
DynaLoader itself returns 0, which produces standard behavior from
|
|
dl_load_file().
|
|
|
|
=item dl_find_symbol()
|
|
|
|
Syntax:
|
|
|
|
$symref = dl_find_symbol($libref, $symbol)
|
|
|
|
Return the address of the symbol $symbol or C<undef> if not found. If the
|
|
target system has separate functions to search for symbols of different
|
|
types then dl_find_symbol() should search for function symbols first and
|
|
then other types.
|
|
|
|
The exact manner in which the address is returned in $symref is not
|
|
currently defined. The only initial requirement is that $symref can
|
|
be passed to, and understood by, dl_install_xsub().
|
|
|
|
SunOS: dlsym($libref, $symbol)
|
|
HP-UX: shl_findsym($libref, $symbol)
|
|
Linux: dld_get_func($symbol) and/or dld_get_symbol($symbol)
|
|
NeXT: rld_lookup("_$symbol")
|
|
VMS: lib$find_image_symbol($libref,$symbol)
|
|
|
|
|
|
=item dl_find_symbol_anywhere()
|
|
|
|
Syntax:
|
|
|
|
$symref = dl_find_symbol_anywhere($symbol)
|
|
|
|
Applies dl_find_symbol() to the members of @dl_librefs and returns
|
|
the first match found.
|
|
|
|
=item dl_undef_symbols()
|
|
|
|
Example
|
|
|
|
@symbols = dl_undef_symbols()
|
|
|
|
Return a list of symbol names which remain undefined after load_file().
|
|
Returns C<()> if not known. Don't worry if your platform does not provide
|
|
a mechanism for this. Most do not need it and hence do not provide it,
|
|
they just return an empty list.
|
|
|
|
|
|
=item dl_install_xsub()
|
|
|
|
Syntax:
|
|
|
|
dl_install_xsub($perl_name, $symref [, $filename])
|
|
|
|
Create a new Perl external subroutine named $perl_name using $symref as
|
|
a pointer to the function which implements the routine. This is simply
|
|
a direct call to newXSUB(). Returns a reference to the installed
|
|
function.
|
|
|
|
The $filename parameter is used by Perl to identify the source file for
|
|
the function if required by die(), caller() or the debugger. If
|
|
$filename is not defined then "DynaLoader" will be used.
|
|
|
|
|
|
=item bootstrap()
|
|
|
|
Syntax:
|
|
|
|
bootstrap($module)
|
|
|
|
This is the normal entry point for automatic dynamic loading in Perl.
|
|
|
|
It performs the following actions:
|
|
|
|
=over 8
|
|
|
|
=item *
|
|
|
|
locates an auto/$module directory by searching @INC
|
|
|
|
=item *
|
|
|
|
uses dl_findfile() to determine the filename to load
|
|
|
|
=item *
|
|
|
|
sets @dl_require_symbols to C<("boot_$module")>
|
|
|
|
=item *
|
|
|
|
executes an F<auto/$module/$module.bs> file if it exists
|
|
(typically used to add to @dl_resolve_using any files which
|
|
are required to load the module on the current platform)
|
|
|
|
=item *
|
|
|
|
calls dl_load_flags() to determine how to load the file.
|
|
|
|
=item *
|
|
|
|
calls dl_load_file() to load the file
|
|
|
|
=item *
|
|
|
|
calls dl_undef_symbols() and warns if any symbols are undefined
|
|
|
|
=item *
|
|
|
|
calls dl_find_symbol() for "boot_$module"
|
|
|
|
=item *
|
|
|
|
calls dl_install_xsub() to install it as "${module}::bootstrap"
|
|
|
|
=item *
|
|
|
|
calls &{"${module}::bootstrap"} to bootstrap the module (actually
|
|
it uses the function reference returned by dl_install_xsub for speed)
|
|
|
|
=back
|
|
|
|
=back
|
|
|
|
|
|
=head1 AUTHOR
|
|
|
|
Tim Bunce, 11 August 1994.
|
|
|
|
This interface is based on the work and comments of (in no particular
|
|
order): Larry Wall, Robert Sanders, Dean Roehrich, Jeff Okamoto, Anno
|
|
Siegel, Thomas Neumann, Paul Marquess, Charles Bailey, myself and others.
|
|
|
|
Larry Wall designed the elegant inherited bootstrap mechanism and
|
|
implemented the first Perl 5 dynamic loader using it.
|
|
|
|
Solaris global loading added by Nick Ing-Simmons with design/coding
|
|
assistance from Tim Bunce, January 1996.
|
|
|
|
=cut
|
|
EOT
|
|
|
|
close OUT or die $!;
|
|
|