Call a C function from Perl used from C

nice has asked for the wisdom of the Perl Monks concerning the following question:

Hello, I have the following example code:


#include <EXTERN.h>
#include <perl.h>

static PerlInterpreter *my_perl;

void hello ()
{
  printf("Hello, world!\n");
}

int main (int argc, char **argv, char **env)
{
  PERL_SYS_INIT3(&argc, &argv, &env);
  my_perl = perl_alloc();
  perl_construct(my_perl);
  PL_exit_flags |= PERL_EXIT_DESTRUCT_END;
  perl_parse(my_perl, NULL, argc, argv, (char **)NULL);
  perl_run(my_perl);
  perl_destruct(my_perl);
  perl_free(my_perl);
  PERL_SYS_TERM();
  
  return 0;
}
[download]

How do I make the "hello" function available to the "my_perl" interpreter?

This case seems to be not covered in documentation.

The closest thing is, probably, to create a separate xs module with a dynamic library and to evaluate "use Separate::Module" statement, exporting necessary subroutines into perl.

Also there is a "newXSproto" function, but I'm not sure how to use it and if it's at all relevant here

Comment on Call a C function from Perl used from C Download Code

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Re: Call a C function from Perl used from C by ikegami (Patriarch) on Mar 28, 2011 at 20:12 UTC
One approach (based on universal.c): `#include <EXTERN.h> #include <perl.h> #include <XSUB.h> XS(XS_Package_sub_name) { ...[ Get arguments from Perl stack ]... rv = sub_name(arg); ...[ Return values on Perl stack ]... } int main() { static const char file[] = __FILE__; ... newXS("Package::sub_name, XS_Package_sub_name, file); ... }` [download] The following are equivalent: `newXS("Package::sub_name, XS_Package_sub_name, file); newXSproto("Package::sub_name, XS_Package_sub_name, file, NULL); newXS_flags("Package::sub_name, XS_Package_sub_name, file, NULL, 0);` [download] By taking this approach, you have to do everything XS would do for you manually. You will probably have a simpler time handling the arguments if you went the route of an XS module. If you do create an XS module, see "Using Perl modules, which themselves use C libraries, from your C program" in perlembed for how to load it up.	[reply] [d/l] [select]
Re^2: Call a C function from Perl used from C by nice (Novice) on Mar 28, 2011 at 21:07 UTC
Wow, thank you for your reply. Here's a working example: #include <EXTERN.h> #include <perl.h> #include <XSUB.h> static PerlInterpreter my_perl; void hello () { printf("Hello, world!\n"); } XS(XS_main_hello) { dXSARGS; if (items != 0) croak_xs_usage(cv, ""); hello(); XSRETURN_EMPTY; } int main (int argc, char argv, char env) { static const char file[] = __FILE__; PERL_SYS_INIT3(&argc, &argv, &env); my_perl = perl_alloc(); perl_construct(my_perl); PL_exit_flags \|= PERL_EXIT_DESTRUCT_END; perl_parse(my_perl, NULL, argc, argv, (char *)NULL); newXS("main::hello", XS_main_hello, file); perl_run(my_perl); perl_destruct(my_perl); perl_free(my_perl); PERL_SYS_TERM(); return 0; } [download]	[reply] [d/l]