This is example I'm looking at https://metacpan.org/pod/perlembed#Fiddling-with-the-Perl-stack-from-your-C-program and I think you could copy this example and turn it into void callback(),

something like 

// static void  PerlPower(int a, int b)
static void callback()
 {
   dSP;                            /* initialize stack pointer      */
   ENTER;                          /* everything created after here */
   SAVETMPS;                       /* ...is a temporary variable.   */
   PUSHMARK(SP);                   /* remember the stack pointer    */
   XPUSHs(sv_2mortal(newSViv(a))); /* push the base onto the stack  */
   XPUSHs(sv_2mortal(newSViv(b))); /* push the exponent onto stack  */
   PUTBACK;                      /* make local stack pointer global */
//   call_pv("expo", G_SCALAR|G_DISCARD|G_NOARGS);      /* call the fu
+nction             */

   call_pv("p_callback", G_DISCARD|G_NOARGS);

   SPAGAIN;                        /* refresh stack pointer         */
                                 /* pop the return value from stack */
//   printf ("%d to the %dth power is %d.\n", a, b, POPi);
   PUTBACK;
   FREETMPS;                       /* free that return value        */
   LEAVE;                       /* ...and the XPUSHed "mortal" args.*/
 }

[download]

Yes , I understand perlcall gives simpler example like you have , but its what I would try, to see if anything sticks :D

In reply to Re^3: XS: Passing an external library's function a Perl XS callback by Anonymous Monk
in thread SOLVED: XS: Passing an external library's function a Perl XS callback by stevieb

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