int test_perlcall( int input ) {
    dSP;  /* Declare and initialize local copy of Perl stack ptr */

    PUSHMARK(SP);
    XPUSHs(sv_2mortal(newSViv( input )));
    PUTBACK;

    if( call_pv( "return_input", G_SCALAR ) != 1 )
        croak( "Well, THAT failed to work.\n" );

    return (int)POPi; /* Inline::C handles this typemap automatically. */
}