nice - change process priority
#include <unistd.h> int nice(int inc);
nice(2) adds inc to the nice value for the calling pid. (A large nice value means a low priority.) Only the super- user may specify a negative increment, or priority increase.
On success, zero is returned. On error, -1 is returned, and errno is set appropriately.
SVr4, SVID EXT, AT
Note that the routine is documented in SUSv2 to return the new nice value, while the Linux syscall and (g)libc (earlier than glibc 2.2.4) routines return 0 on success. The new nice value can be found using getpriority(2). Note that an implementation in which nice returns the new nice value can legitimately return -1. To reliably detect an error, set errno to 0 before the call, and check its value when nice returns -1.
nice(1), getpriority(2), setpriority(2), fork(2), renice(8)?
8 pages link to nice(2):