NAME    [Toc]    [Back]

       nice - Change the scheduling priority of a process

SYNOPSIS    [Toc]    [Back]

       #include <unistd.h>

       int nice(
               int increment );

LIBRARY    [Toc]    [Back]

       Standard C Library (libc)

       Berkeley Compatibility Library (libbsd)

STANDARDS    [Toc]    [Back]

       Interfaces  documented  on  this reference page conform to
       industry standards as follows:

       nice(): XSH4.2

       Refer to the standards(5) reference page for more information
 about industry standards and associated tags.

PARAMETERS    [Toc]    [Back]

       Specifies  a  value  that  is added to the current process
       priority. You can specify a negative value.

DESCRIPTION    [Toc]    [Back]

       The nice() function adds the value specified in the increment
  parameter  to the nice value of the calling process.
       The nice value is a  nonnegative  number;  a  higher  nice
       value gives the process a lower CPU priority.

       When  you  are using the Standard C Library version of the
       nice() function, the maximum nice value for a  process  is
       39  (2 * {NZERO} -1) and the minimum is 0 (zero). Requests
       for values outside these limits result in the  nice  value
       being set to the corresponding limit.

       [XPG4-UNIX]  If execution of the Standard C Library nice()
       function fails, the system does not  alter  the  specified
       priority.

       Any  process can lower its priority (numerically raise its
       nice value). A process must have superuser  privileges  to
       raise its priority (numerically lower its nice value).

       [Tru64 UNIX]  For backward compatibility, a version of the
       nice() function is supported that allows  nice  values  in
       the range of -20 to 20. Requests for values above or below
       these limits result in the nice value  being  set  to  the
       corresponding  limit.  To use the backward-compatible version
 of nice(), compile with  the  Berkeley  Compatibility
       Library (libbsd.a).

RETURN VALUES    [Toc]    [Back]

       Upon  successful  completion,  the nice() function returns
       the new nice value  minus  20  ({NZERO}).  Otherwise,  the
       function  returns -1 and sets errno to indicate the error.

ERRORS    [Toc]    [Back]

       The Standard C Library version of nice() sets errno to the
       specified values for the following conditions: The calling
       process does not have appropriate privilege.

       [Tru64 UNIX]  The libbsd.a version of nice() sets errno to
       the  same values as the setpriority() function. For information
 about possible return values for the  setpriority()
       function, see setpriority(2).

SEE ALSO    [Toc]    [Back]

       Functions: exec(2), getpriority(2), setpriority(2)

       Standards: standards(5)



                                                          nice(3)