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NICE(3) FreeBSD Library Functions Manual NICE(3)
NAME
nice - set program scheduling priority
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <unistd.h>
int
nice(int incr);
DESCRIPTION
This interface is obsoleted by setpriority(2).
The nice() function adds incr to the scheduling priority of the process.
The priority is a value in the range -20 to 20. The default priority is
0; lower priorities cause more favorable scheduling. Only the super-user
may lower priorities.
Children inherit the priority of their parent processes via fork(2).
RETURN VALUES
Upon successful completion, nice() returns 0, and errno is unchanged.
Otherwise, -1 is returned, the process' nice value is not changed, and
errno is set to indicate the error.
ERRORS
The nice() function will fail if:
[EPERM] The incr argument is negative and the caller does not
have appropriate privileges.
SEE ALSO
nice(1), fork(2), setpriority(2), renice(8)
STANDARDS
The nice() function conforms to IEEE Std 1003.1-2008 ("POSIX.1") except
for the return value. This implementation returns 0 upon successful
completion but the standard requires returning the new nice value, which
could be -1.
HISTORY
A nice() syscall appeared in Version 6 AT&T UNIX.
FreeBSD 14.0-RELEASE-p6 February 28, 2015 FreeBSD 14.0-RELEASE-p6