Hi,
I had always assumed that if, in XS, we wanted to return items from the stack to perl, we had to do an XSRETURN(x) where x is the number of items we want to return.

Apparently that's not so. The below Inline::C script doesn't explicitly return anything, yet the 3 values that are pushed onto the stack are returned: 
use warnings;

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


use Inline C => <<'EOC';

void foo() {
     dXSARGS;
     sp = mark;
     XPUSHs(sv_2mortal(newSVuv(111))); 
     XPUSHs(sv_2mortal(newSVuv(87)));
     XPUSHs(sv_2mortal(newSVuv(42))); 
     PUTBACK;
}

EOC

@bar = foo();
print "@bar\n"; # prints 111 87 42

[download]
There's also a demo in the Inline::C-Cookbook that returns values in the same way without an explicit XSRETURN(x).

If no explicit XSRETURN(x) is made, and the function is void, is it simply the case that everything that has been pushed onto the stack is returned ? Is this behaviour reliable ?

Cheers,
Rob

In reply to [XS] Correct way to return the stack by syphilis

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