sched_get_priority_min(2) [linux man page]

SCHED_GET_PRIORITY_MAX(2)				     Linux Programmer's Manual					 SCHED_GET_PRIORITY_MAX(2)

NAME

       sched_get_priority_max, sched_get_priority_min  - get static priority range

SYNOPSIS

       #include <sched.h>

       int sched_get_priority_max(int policy);

       int sched_get_priority_min(int policy);

DESCRIPTION

       sched_get_priority_max()  returns  the  maximum	priority  value  that  can  be	used  with  the scheduling algorithm identified by policy.
       sched_get_priority_min() returns the minimum priority value that can be used with the scheduling algorithm identified by policy.  Supported
       policy values are SCHED_FIFO, SCHED_RR, SCHED_OTHER, and SCHED_BATCH.  Further details about these policies can be found in sched_setsched-
       uler(2).

       Processes with numerically higher priority values are scheduled before processes with numerically lower priority values.  Thus,	the  value
       returned by sched_get_priority_max() will be greater than the value returned by sched_get_priority_min().

       Linux  allows  the  static  priority  value  range  1 to 99 for SCHED_FIFO and SCHED_RR and the priority 0 for SCHED_OTHER and SCHED_BATCH.
       Scheduling priority ranges for the various policies are not alterable.

       The range of scheduling priorities may vary on other POSIX systems, thus it is a good idea for portable applications to use a virtual  pri-
       ority  range  and map it to the interval given by sched_get_priority_max() and sched_get_priority_min().  POSIX.1-2001 requires a spread of
       at least 32 between the maximum and the minimum values for SCHED_FIFO and SCHED_RR.

       POSIX systems on which sched_get_priority_max() and sched_get_priority_min() are available define _POSIX_PRIORITY_SCHEDULING in <unistd.h>.

RETURN VALUE

       On success, sched_get_priority_max() and sched_get_priority_min() return the maximum/minimum priority value for the named  scheduling  pol-
       icy.  On error, -1 is returned, and errno is set appropriately.

ERRORS

       EINVAL The argument policy does not identify a defined scheduling policy.

CONFORMING TO

       POSIX.1-2001.

SEE ALSO

       sched_getaffinity(2), sched_getparam(2), sched_getscheduler(2), sched_setaffinity(2), sched_setparam(2), sched_setscheduler(2)

       Programming for the real world - POSIX.4 by Bill O. Gallmeister, O'Reilly & Associates, Inc., ISBN 1-56592-074-0

COLOPHON

       This  page is part of release 3.27 of the Linux man-pages project.  A description of the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

Linux								    2006-03-23						 SCHED_GET_PRIORITY_MAX(2)

Check Out this Related Man Page

SCHED_GET_PRIORITY_MAX(2)				      BSD System Calls Manual					 SCHED_GET_PRIORITY_MAX(2)

NAME

     sched_get_priority_max, sched_get_priority_min, sched_rr_get_interval -- get scheduling parameter limits

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <sched.h>

     int
     sched_get_priority_max(int policy);

     int
     sched_get_priority_min(int policy);

     int
     sched_rr_get_interval(pid_t pid, struct timespec *interval);

DESCRIPTION

     The sched_get_priority_max() and sched_get_priority_min() system calls return the appropriate maximum or minimum, respectively, for the
     scheduling policy specified by policy.  The sched_rr_get_interval() system call updates the timespec structure referenced by the interval
     argument to contain the current execution time limit (i.e., time quantum) for the process specified by pid.  If pid is zero, the current exe-
     cution time limit for the calling process is returned.

     The value of policy should be one of the scheduling policy values defined in <sched.h>:

     [SCHED_FIFO]   First-in-first-out fixed priority scheduling with no round robin scheduling;

     [SCHED_OTHER]  The standard time sharing scheduler;

     [SCHED_RR]     Round-robin scheduling across same priority processes.

RETURN VALUES

     If successful, the sched_get_priority_max() and sched_get_priority_min() system calls shall return the appropriate maximum or minimum values,
     respectively.  If unsuccessful, they shall return a value of -1 and set errno to indicate the error.

     The sched_rr_get_interval() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is
     set to indicate the error.

ERRORS

     On failure errno will be set to the corresponding value:

     [EINVAL]		The value of the policy argument does not represent a defined scheduling policy.

     [ENOSYS]		The sched_get_priority_max(), sched_get_priority_min(), and sched_rr_get_interval() system calls are not supported by the
			implementation.

     [ESRCH]		No process can be found corresponding to that specified by pid.

SEE ALSO

     sched_getparam(2), sched_getscheduler(2), sched_setparam(2), sched_setscheduler(2)

STANDARDS

     The sched_get_priority_max(), sched_get_priority_min(), and sched_rr_get_interval() system calls conform to IEEE Std 1003.1b-1993
     (``POSIX.1'').

BSD
								  March 12, 1998							       BSD

Linux and UNIX Man Pages

sched_get_priority_min(2) [linux man page]

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