Calling RPGILE program from C

First the code:

*#include <stdio.h>*
*#include <string.h>*

*#include <decimal.h>
#include <stdlib.h>

typedef void RGTRIGCNTL(char[80], decimal(10,0));

#pragma linkage(RGTRIGCNTL,fetchable)

int main(int argc, char *argv[])
{
char *triggerInfo;
decimal (10,0) triggerLen;

triggerInfo = argv[1];
triggerLen = argv[2];

RGTRIGCNTL(triggerInfo, &triggerLen);
}*

*What's going on: trying to write a small C program to attach to file triggers.*

Problems:

pragma linkage won't allow 'OS' for a parameter. Everything I've read
indicates that's what I want. The only "ID' compiler didn't barf on is
'fetchable', which is why its there.

It compiles, but nothing happens when I try to step into RGTRIGCNTL.

The Dev box is V5R4 (long story).

The questions:

Why can't I use 'OS' in linkage? Why isn't my program getting called?

The last time I wrote a C program was in college, a looong time ago.