nice (2)

NAME

       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 superuser 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  nonstandard,  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 (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.

SEE ALSO

       nice(1), getpriority(2), setpriority(2), fork(2), renice(8)

Linux                             2001-06-04                           nice(2)