3.2.141 setpriority

setpriority 

WHICH

, 

WHO

, 

PRIORITY

This function sets the current priority for a process, a process group, or a user. See setpriority (2). Invoking setpriority will produce a fatal error if used on a machine that doesn't implement setpriority (2). To "nice" your process down by four units (the same as executing your program with nice (1)), try:

setpriority 0, 0, getpriority(0, 0) + 4;

The interpretation of a given priority may vary from one operating system to the next.