Stored Procedure Question

Does anyone know of a way to uniquely identify an instance of a stored procedure call within the stored procedure? My problem is that I am doing a system call within the stored procedure to execute a program that takes a very large parameter list. There seems to be a 256 character limit on a string passed to a system call within a stored procedure, so what I was trying to do is write the executable call to a file via a number of system calls then execute that. The problem with this approach is that I need to uniquely identify the file I am writing to per stored procedure instance because there is a good chance that multiple instances could be executing at the same time. Any ideas? Informix support is working on it but I thought I'd check here just in case. Regards, Julie Julie C. Jumes Bell Northern Research jumes@bnr.ca