7.2.22 ExtUtils::Mksymlists - Write Linker Option Files for Dynamic Extension

use ExtUtils::Mksymlists;

Mksymlists(  NAME     => $name,
             DL_FUNCS => { $pkg1 => [$func1, $func2], $pkg2 => [$func3] },
             DL_VARS  => [$var1, $var2, $var3]);

ExtUtils::Mksymlists() produces files used by the linker under some OSes during the creation of shared libraries for dynamic extensions. It is normally called from a MakeMaker-generated Makefile when the extension is built. The linker option file is generated by calling the function Mksymlists(), which is exported by default from ExtUtils::Mksymlists. It takes one argument, a list of key/value pairs, in which the following keys are recognized:

NAME

This gives the name of the extension (for example, Tk::Canvas) for which the linker option file will be produced.

DL_FUNCS

This is identical to the DL_FUNCS attribute available via MakeMaker, from which it is usually taken. Its value is a reference to a hash, in which each key is the name of a package, and each value is a reference to an array of function names, which should be exported by the extension. So, one might say:

DL_FUNCS => {
     Homer::Iliad   => [ qw(trojans greeks) ],
     Homer::Odyssey => [ qw(travelers family suitors) ],
},

The function names should be identical to those in the XSUB code; Mksymlists() will alter the names written to the linker option file to match the changes made by xsubpp. In addition, if none of the functions in a list begins with the string "boot_", Mksymlists() will add a bootstrap function for that package, just as xsubpp does. (If a boot_pkg function is present in the list, it is passed through unchanged.) If DL_FUNCS is not specified, it defaults to the bootstrap function for the extension specified in NAME.

DL_VARS

This is identical to the DL_VARS attribute available via MakeMaker, and, like DL_FUNCS, it is usually specified via MakeMaker. Its value is a reference to an array of variable names that should be exported by the extension.

FILE

This key can be used to specify the name of the linker option file (minus the OS-specific extension) if for some reason you do not want to use the default value, which is the last word of the NAME attribute (for example, for Tk::Canvas, FILE defaults to Canvas).

FUNCLIST

This provides an alternate means to specify function names to be exported from the extension. Its value is a reference to an array of function names to be exported. These names are passed through unaltered to the linker options file.

DLBASE

This item specifies the name by which the linker knows the extension, which may be different from the name of the extension itself (for instance, some linkers add an "_" to the name of the extension). If it is not specified, it is derived from the NAME attribute. It is presently used only by OS/2.

When calling Mksymlists(), one should always specify the NAME attribute. In most cases, this is all that's necessary. In the case of unusual extensions, however, the other attributes can be used to provide additional information to the linker.