Perl in a Nutshell, 2nd Edition

Extending to New Architectures

If you want to extend DynaLoader to a new architecture, you need to know about its internal interface. The variables it uses are:

$dl_debug

Enables internal debugging messages on the Perl side of the DynaLoader; by default, is set to $ENV{'PERL_DL_DEBUG'} if that is defined. A similar debugging variable is added to the C code (see dlutils.c) and enabled if Perl was built with the -DDEBUGGING flag, or it can be set via the PERL_DL_DEBUG environment variable. Set to 1 for minimal information or higher for more detail.

@dl_library_path

Default list of directories to search for libraries; initialized to hold the list of directories in $Config{'libpth'}. Should also be initialized with other directories that can be determined from the environment at runtime.

@dl_resolve_using

List of additional libraries or other shared objects for resolving undefined symbols. Required only on platforms without automatic handling for dependent libraries.

@dl_require_symbols

List of one or more symbol names in the library/object file to be dynamically loaded. Only required on some platforms.

Of the following subroutines, bootstrap and dl_findfile are standard across all platforms and are defined in DynaLoader.pm. The others are defined in the .xs file that supplies the implementation for the platform.