sched_setparam()
Change the priority of a process
Synopsis:
#include <sched.h> int sched_setparam( pid_t pid, const struct sched_param *param );
Arguments:
- pid
- The ID of the process whose priority you want to set, or 0 to set it for the current process.
- param
- A pointer to a sched_param structure whose sched_priority member holds the priority that you want to assign to the process.
Library:
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
Description:
The sched_setparam() function changes the priority of process pid to that of the sched_priority member in the sched_param structure pointed to by param. If pid is zero, the priority of the calling process is changed.
The sched_priority member in param must lie between the minimum and maximum values returned by sched_get_priority_max() and sched_get_priority_min() .
By default, the process priority and scheduling policy are inherited from or explicitly set by the parent process. Once running, the child process may change its priority by using this function.
Returns:
- 0
- Success
- -1
- An error occurred (errno is set).
Errors:
- EFAULT
- A fault occurred trying to access the buffers provided.
- EINVAL
- The priority isn't a valid priority.
- EPERM
- The calling process doesn't have the required permission; see procmgr_ability() .
- ESRCH
- The process pid doesn't exist.
Classification:
Safety: | |
---|---|
Cancellation point | No |
Interrupt handler | No |
Signal handler | Yes |
Thread | Yes |
Caveats:
In a multithreaded program, sched_setparam() sets the scheduling parameters for thread 1 in the process pid, or for the calling thread if pid is 0.