Functions with variable numbers of arguments - Functions with variable number of arguments (vararg, stdarg, va_arg, etc.)

Algorithms - sorting, searching, etc.

Process Creation and Control - covers child process control (like sending signals), renice, fork, et al

Data structures (In memory) - Data structures in memory. Queues, lists, graphs, trees, etc.

Debugging and Tracing - (utilities, system and library calls which support debugging and tracing)

Real-Time related - time of day, elapsed time, sleeping, waiting for events. time(), gmtime(), localtime(), etc.

Math - Gateway topic to math and numeric processing routines.

Subject divisions directly under this one are #here#.