-open(my $callfh, '>', 'GENERATED_call.h');
-say $callfh 'static char *GENERATED_call(const int call_identifier) {';
-say $callfh ' char *output = NULL;';
+open(my $callfh, '>', "GENERATED_${prefix}_call.h");
+say $callfh 'static void GENERATED_call(const int call_identifier, struct CommandResult *result) {';