nice - change process priority
SYNOPSIS
#include <unistd.h>
int nice(int inc);
DESCRIPTION
nice 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.
RETURN VALUE
On success, zero is returned. On error, -1 is returned,
and errno is set appropriately.
ERRORS
EPERM A non-super user attempts to do a priority increase
by supplying a negative inc.
CONFORMING TO
SVr4, SVID EXT, AT&T, X/OPEN, BSD 4.3. However, the Linux
and glibc (earlier than glibc 2.2.4) return value is non
standard, see below. SVr4 documents an additional EINVAL
error code.
NOTES
Note that the routine is documented in SUSv2 to return the
new nice value, while the Linux syscall and (g)libc (ear
lier 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.
SEE ALSO
nice(1), getpriority(2), setpriority(2), fork(2),
renice(8)
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