Writing cross-platform apps in C

Question

What things should be kept most in mind when writing cross-platform applications in C? Targeted platforms: 32-bit Intel based PC, Mac, and Linux. I\'m especially looking for

Answer 1

There do exist quite few portable libraries just examples I've worked within the past

1) glib and gtk+

2) libcurl

3) libapr

Those cover nearly every platform and so they are extremly useful tool.

Posix is fine on Unices but well I doubt it's that great on windows, besides we do not have any stuff for portable GUIs there.