A program I have written will be ran on Windows as a normal user. An installer I have created will install it into the C:\Program Files directory. I will need to use tmpfile(); for many things. Is this effective or is there a better method? Would the system deny the program the ability to use tmpfile(); because the program is being ran from that directory? I have used tmpfile(); in a variety of situations and it has never returned NULL for me, and I need it to still be reliable in this situation. What would make it return NULL, and why? Do I have nothing to worry about? Thanks!