I'm unsure about how to call a routine located in another XS module from within an XS module

One solution - if, in Foo.xs, we want to access a function (let's call it 'bar') from Bar.xs, then we have the Bar module make available a pointer to the bar function. The Foo.xs functions then access the bar function via that pointer.

I have a full but minimal working demo of this principle on this machine. I could put copies of the files (Foo.pm, Bar.pm, Foo.xs, Bar.xs, Makefile.PL's and test.pl's) on my scratchpad if that's going to serve any purpose. Note that, with this approach, you'll probably be making significant alterations to both source distros. I think it's the best approach to calling xsubs in one extension from xsubs in another extension .... but I'm not so sure that this is the best way for you to achieve your ends in this particular case.

For a basic demo of passing functions by pointer, here's an Inline::C script that creamygoodness posted a while back: 
use strict;
use warnings;

use Inline C => Config =>
    BUILD_NOISY => 1;

use Inline C => <<'END_C';

typedef void
(*hello_func_t)(SV * x);

typedef SV * 
(*sv_func_t)(SV * x);

void
hola_mundo(SV * x)
{
    printf("Hola, mundo! %d\n", (int)SvIV(x));
}

SV *
hola_mundo2(SV *x) {
    printf("Hola, mundo2! %d\n", (int)SvIV(x));
    return newSViv((int)SvIV(x) * 2);
}


SV*
get_hola_mundo_func_ptr()
{
    return newSViv( PTR2IV(hola_mundo) );
}

SV*
get_hola_mundo2_func_ptr()
{
    return newSViv( PTR2IV(hola_mundo2) );
}

void
do_hello(SV *sv_with_func_ptr, SV * x)
{
    IV temp = SvIV(sv_with_func_ptr);
    hello_func_t hello = INT2PTR(hello_func_t, temp);
    hello(x);
}

SV *
do_hello2(SV *sv_with_func_ptr, SV * x)
{
    IV temp = SvIV(sv_with_func_ptr);
    sv_func_t hello = INT2PTR(sv_func_t, temp);
    return hello(x);
}


END_C

my $num = 123458;
my $func_ptr = get_hola_mundo_func_ptr();
do_hello($func_ptr, $num);

my $func_ptr2 = get_hola_mundo2_func_ptr();
my $ret = do_hello2($func_ptr2, $num);
print $ret;

[download]
Cheers,
Rob

In reply to Re^3: Pursuading an XS module to use a routine from another XS module. by syphilis
in thread Pursuading an XS module to use a routine from another XS module. by BrowserUk

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