RFC 121 (v1) linkable output mode

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=head1 TITLE

linkable output mode

=head1 VERSION

  Maintainer: David Nicol <[email protected]>
  Date: 17 Aug 2000
  Version: 1
  Mailing List: [email protected]
  Number: 121

=head1 ABSTRACT


Perl5 offers a clunky interface for those who
wish to call perl subroutines from within C programs.
Herein is suggested a vastly simplified application
programmer's interface:  a C< -o > command line switch identical
to that used in C compilers to produce a linkable object file.


=head1 DESCRIPTION

Two command line switches, -o and -oh, are added to perl6's invocation syntax.

Perl invoked with the -o switch does not run its program, but rather
pukes out an "object file" same way gcc would if given a file full of
C code.

Perl invoked with the -oh switch does not run its program, but rather
pukes out a "header file" suitable for inclusion into a C program,
containing the correct linkage definitions for the object file created
by the -o switch.

The resulting object file must be linked with the perl library to work.

The point is, the perl internals are effectively hidden from the programmer
who wishes to use a feature available in perl from within a C program.

Much is left unspecified.

=head1 IMPLEMENTATION

Given a nonprototyped subroutine, C<perl6 -o> will
generate suitable wrapper
code for all subroutines in the input file, as described in the L<perlcall>
and L<perlembed> perldoc pages, and then pass this code (via a temporary file)
to the same C compiler that was used to build perl.

Given a perl6 subroutine with a fully described prototype, which amounts
to a C struct structure, that structure (with its names if any) can
be used as the parameter types of the resulting function call. A restricted
return type described in terms of basic C data types can function as a
C function return type.

Perl functions that are already using restricted parameter lists
and restricted return types are effectively doing their own type conversions,
except between SV{STRING} and char*, but allowing C access to the SV{STRING}
data type and functions can't be anything but good.


=head1 REFERENCES

my imagination

perldoc perlembed

perldoc perlcall