ExtUtils::Liblist::ext($self, $potential_libs, $verbose);
It returns an array of four scalar values: EXTRALIBS, BSLOADLIBS, LDLOADLIBS, and LD_RUN_PATH. Some of these don't mean anything on VMS and Win32. See the details about those platform specifics below.
Dependent libraries can be linked in one of three ways:
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.
An entry of the form -La:\foo specifies the a:\foo directory to look for the libraries that follow.
An entry of the form -lfoo specifies the library foo, which may be spelled differently depending on what kind of compiler you are using. If you are using GCC, it gets translated to libfoo.a, but for other win32 compilers, it becomes foo.lib. If no files are found by those translated names, one more attempt is made to find them using either foo.a or libfoo.lib, depending on whether GCC or some other win32 compiler is being used, respectively.
If neither the -L or -l prefix is present in an entry, the entry is considered a directory to search if it is in fact a directory, and a library to search for otherwise. The $Config{lib_ext} suffix will be appended to any entries that are not directories and don't already have the suffix.
Note that the -L and <-l> prefixes are not required, but authors
who wish their extensions to be portable to Unix or OS/2 should use the
prefixes, since the Unix-OS/2 version of ext() requires them.
An entry that matches /:nodefault/i disables the appending of default libraries found in $Config{libs} (this should be only needed very rarely).
An entry that matches /:nosearch/i disables all searching for the libraries specified after it. Translation of -Lfoo and -lfoo still happens as appropriate (depending on compiler being used, as reflected by $Config{cc}), but the entries are not verified to be valid files or directories.
An entry that matches /:search/i reenables searching for
the libraries specified after it. You can put it at the end to
enable searching for default libraries specified by $Config{libs}.
"-Lc:\Program Files\vc\lib" msvcrt.lib "la test\foo bar.lib"Note how the first and last entries are protected by quotes in order to protect the spaces.
LIBS => ['-lgl']When using GCC, that entry specifies that MakeMaker should first look for libgl.a (followed by gl.a) in all the locations specified by $Config{libpth}.
When using a compiler other than GCC, the above entry will search for gl.lib (followed by libgl.lib).
If the library happens to be in a location not in $Config{libpth}, you need:
LIBS => ['-Lc:\gllibs -lgl']Here is a less often used example:
LIBS => ['-lgl', ':nosearch -Ld:\mesalibs -lmesa -luser32']This specifies a search for library gl as before. If that search fails to find the library, it looks at the next item in the list. The :nosearch flag will prevent searching for the libraries that follow, so it simply returns the value as -Ld:\mesalibs -lmesa -luser32, since GCC can use that value as is with its linker.
When using the Visual C compiler, the second item is returned as -libpath:d:\mesalibs mesa.lib user32.lib.
When using the Borland compiler, the second item is returned as -Ld:\mesalibs mesa.lib user32.lib, and MakeMaker takes care of moving the -Ld:\mesalibs to the correct place in the linker command line.