C :: Accessing Files From Multiple Processors

I have a big un-editable program, A, which I need to run for like a 1000 different input files. It takes about 15 minutes for each file, so a little parallelisation wouldn't hurt.

I have installed openmpi and it works fine. I have made a small program, B, which selects an input file, moves it to another directory, calls program A with the path to the selected input file and then - when A is done - selects a new input file etc. It should loop until there are no more files in the initial directory.

The problem is this: When I have several processors they might pick the same file and that leads to errors. I have a working program, but it is not pretty.

Code:

#include <stdio.h>
#include <mpi.h>
#include <dirent.h>
#include <string.h>
#include <stdlib.h>
int main(int argc, char *argv[]) {
int num_procs, procs_id, i, exit;
struct dirent *ent;

[Code]...

Every time a processor tries to move a file that another processor has just moved, the output shows an error message before looping to the next file and trying again. It works, but it is a bit annoying. So my questions are:

1) Can I switch off the error message somehow?

2) Is there a better way to do this?