You are viewing the version of this documentation from Perl 5.40.0-RC2. This is a development version of Perl.



ExtUtils::Liblist - determine libraries to use and how to use them


require ExtUtils::Liblist;

$MM->ext($potential_libs, $verbose, $need_names);

# Usually you can get away with:
ExtUtils::Liblist->ext($potential_libs, $verbose, $need_names)


This utility takes a list of libraries in the form -llib1 -llib2 -llib3 and returns lines suitable for inclusion in an extension Makefile. Extra library paths may be included with the form -L/another/path this will affect the searches for all subsequent libraries.

It returns an array of four or five scalar values: EXTRALIBS, BSLOADLIBS, LDLOADLIBS, LD_RUN_PATH, and, optionally, a reference to the array of the filenames of actual libraries. Some of these don't mean anything unless on Unix. See the details about those platform specifics below. The list of the filenames is returned only if $need_names argument is true.

Dependent libraries can be linked in one of three ways:


List of libraries that need to be linked with when linking a perl binary which includes this extension. Only those libraries that actually exist are included. These are written to a file and used when linking perl.


List of those libraries which can or must be linked into the shared library when created using ld. These may be static or dynamic libraries. LD_RUN_PATH is a colon separated list of the directories in LDLOADLIBS. It is passed as an environment variable to the process that links the shared library.


List of those libraries that are needed but can be linked in dynamically at run time on this platform. SunOS/Solaris does not need this because ld records the information (from LDLOADLIBS) into the object file. This list is used to create a .bs (bootstrap) file.


This module deals with a lot of system dependencies and has quite a few architecture specific ifs in the code.

VMS implementation

The version of ext() which is executed under VMS differs from the Unix-OS/2 version in several respects:

In addition, an attempt is made to recognize several common Unix library names, and filter them out or convert them to their VMS equivalents, as appropriate.

In general, the VMS version of ext() should properly handle input from extensions originally designed for a Unix or VMS environment. If you encounter problems, or discover cases where the search could be improved, please let us know.

Win32 implementation

The version of ext() which is executed under Win32 differs from the Unix-OS/2 version in several respects: