Digital

NAME

sched_get_sched_param − return the scheduling parameters of the specified process (P1003.4/D10)

SYNOPSIS

#include <sched.h>

int sched_get_sched_param (
pid_t pid ,
struct sched_param ∗param) ;

PARAMETERS

pid The process identification of the process whose scheduling parameters are returned. If pid is zero, the scheduling parameters of the calling process are returned. 

param A pointer to a sched_param structure, which contains the scheduling parameters of the calling process.  The value of the priority field in the param structure is the current priority of process specified by the pid. The sched_param structure is defined in <sched.h>. 

DESCRIPTION

The sched_get_sched_param function returns the scheduling parameters of a process. If the pid is zero, the scheduling parameters are returned for the calling process. 

Use the sched_set_sched_param function to change the scheduling parameters. 

Currently, the sched_param structure contains only a priority field. 

The priority of a process is inherited across fork and exec calls. 

An application designed for portability must initialize all fields of the sched_param structure before making the function call. 

No special privileges are needed to use the sched_get_sched_param function. 

RETURN VALUES

On a successful call to the sched_get_sched_param function, a value of 0 is returned. On an unsuccessful call, a value of −1 is returned and errno is set to indicate that an error occurred and the specified priority is unchanged. 

ERRORS

The sched_get_sched_param function fails under the following conditions:

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

[ENOSYS] P1003.4/D10 priority scheduling is not configured in this implementation.  Refer to the DEC OSF/1 Realtime Installation Guide for information on how to install the realtime software. 

[EINVAL] The param pointer is NULL, or one or more of the parameters contained in it is outside the valid range for the specified scheduling policy. 

RELATED INFORMATION

getpid(2), sched_getscheduler(3), sched_set_sched_param(3), sched_setscheduler(3)