Dragon writes: > My code compiles fine with gcc. 4.1.1 > > gcc /home/path/indo18b.c -o /home/path/indo18b -lm -lz > I have traced the offending line to the fopen statement. Read through all > documentation I could find that indicates I am not doing anything really > strange or wrong. Yes, you are. > Am I missing something? > > Please suggest solution....I am using Fedora Core 5. Embarrassingly, I admit I > am unsure how to adjust the heap or stack. You're trashing memory with a wild pointer write somewhere in your code. Valgrind is a good tools to use at this point. Andrew.