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Change the priority of a process
#include <sched.h> int sched_setparam( pid_t pid, const struct sched_param *param );
- The ID of the process whose priority you want to set, or 0 to set it for the current process.
- A pointer to a sched_param structure whose sched_priority member holds the priority that you want to assign to the process.
Use the -l c option to qcc to link against this library. This library is usually included automatically.
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.
By default, the process priority and scheduling algorithm are inherited from or explicitly set by the parent process. Once running, the child process may change its priority by using this function.
- An error occurred (errno is set).
- A fault occurred trying to access the buffers provided.
- The priority isn't a valid priority.
- The calling process doesn't have sufficient privilege to set the priority.
- The process pid doesn't exist.
Currently, the implementation of sched_setparam() isn't 100% POSIX 1003.1-1996. The sched_setparam() function sets the scheduling parameters for thread 1 in the process pid, or for the calling thread if pid is 0.
If you depend on this in new code, it will not be portable. POSIX 1003.1 says sched_setparam() should return -1 and set errno to EPERM in a multithreaded application.