The XS code could modify its iReturn and output the changes. Your C code is modifying an iReturn that is simply a copy and those changes don't leave the C code and XS can't do anything to change that.

If you want to have a C routine change a parameter, then you have to pass the parameter by reference. 

.XS file: 
#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"
#include <TestInclude.h>
MODULE = TEST        PACKAGE = TEST
        
void
C_function(iReturn)
        int           &iReturn
    OUTPUT:
        iReturn


C function: 
#include "TestInclude.h"

void C_function( int *iReturn )
{
    *iReturn = 5;
}


.H prototype: 
void  C_function( int *iReturn );

[download]

Untested.

- tye        

In reply to Re: Perl extension parameters (by ref) by tye
in thread Perl extension parameters by timfar

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