Pointers to functions in C ? ... then wrapped in an SV ?
C function pointers are directly analogous to perl subroutine references. The big differences are...
- They're typed, so function signatures must match.
- The syntax for declaring them is bloody awful. In fact, it's so awful that many people use typedefs whenever possible.
- You can't verify that a non-NULL function pointer actually points to anything valid, unlike in Perl where you can verify a sub ref with ref($sub).
Here's a demo for passing a function pointer around via SV.
use strict;
use warnings;
use Inline C => <<'END_C';
typedef void
(*hello_func_t)();
void
hola_mundo()
{
printf("Hola, mundo!\n");
}
SV*
get_hola_mundo_func_ptr()
{
return newSViv( PTR2IV(hola_mundo) );
}
void
do_hello(SV *sv_with_func_ptr)
{
IV temp = SvIV(sv_with_func_ptr);
hello_func_t hello = INT2PTR(hello_func_t, temp);
hello();
}
END_C
my $func_ptr = get_hola_mundo_func_ptr();
do_hello($func_ptr);