Perl 5 DynaLoader

See DynaLoader.pm for detailed specification.

This module is very similar to the other Perl 5 modules except that
Configure selects which dl_*.xs file to use.

After Configure has been run the Makefile.PL will generate a Makefile
which will run xsubpp on a specific dl_*.xs file and write the output
to DynaLoader.c

After that the processing is the same as any other module.

Note that, to be effective, the DynaLoader module must be _statically_
linked into perl! Configure should arrange this.

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 and others.

The dl_*.xs files should either be named after the dynamic linking
operating system interface used if that interface is available on more
than one type of system, e.g.:
	dlopen  for dlopen()/dlsym() type functions (SunOS, BSD)
or else the osname, e.g., hpux, next, vms etc.

Both are determined by Configure and so only those specific names that
Configure knows/uses will work.

If porting the DynaLoader to a platform that has a core dynamic linking
interface similar to an existing generic type, e.g., dlopen,
please try to port the corresponding dl_*.xs file (using #ifdef's if
required).

Otherwise, or if that proves too messy, create a new dl_*.xs file named
after your osname. Configure will give preference to a dl_$osname.xs
file if one exists.

The file dl_dlopen.xs is a reference implementation by Paul Marquess
which is a good place to start if porting from scratch. The dlutils.c file
holds some common definitions that are #included into the dl_*.xs files.

After the initial implementation of a new DynaLoader dl_*.xs file you
may need to edit or create ext/MODULE/MODULE.bs files (library bootstrap
files) to reflect the needs of your platform and linking software.

Refer to DynaLoader.pm, lib/ExtUtils/MakeMaker.pm and any existing
ext/MODULE/MODULE.bs files for more information.

Tim Bunce.
August 1994
