BSD syscall#96
svc · unix #96
setpriority
Sets the scheduling nice value for a process, group, or user.
Prototype
int setpriority(int which, id_t who, int prio);Returns: int
Arguments
| Name | Type | Dir | Description |
|---|---|---|---|
| which | int | - | |
| who | id_t | - | |
| prio | int | - |
Version history
| XNU tag | macOS | # |
|---|---|---|
| xnu-1456.1.26 | macOS 10.6 Snow Leopard | 96 |
| xnu-1699.24.8 | macOS 10.7 Lion | 96 |
| xnu-2050.18.24 | macOS 10.8 Mountain Lion | 96 |
| xnu-2422.115.4 | macOS 10.9 Mavericks | 96 |
| xnu-1486.2.11 | — | 96 |
| xnu-1504.15.3 | — | 96 |
| xnu-1504.3.12 | — | 96 |
| xnu-1504.7.4 | — | 96 |
| xnu-1504.9.17 | — | 96 |
| xnu-1504.9.26 | — | 96 |
| xnu-1504.9.37 | — | 96 |
| xnu-1699.22.73 | — | 96 |
| xnu-1699.22.81 | — | 96 |
| xnu-1699.24.23 | — | 96 |
| xnu-1699.26.8 | — | 96 |
| xnu-1699.32.7 | — | 96 |
| xnu-2050.22.13 | — | 96 |
| xnu-2050.24.15 | — | 96 |
| xnu-2050.48.11 | — | 96 |
| xnu-2050.7.9 | — | 96 |
| xnu-2050.9.2 | — | 96 |
| xnu-2422.1.72 | — | 96 |
| xnu-2422.100.13 | — | 96 |
| xnu-2422.110.17 | — | 96 |
| xnu-2422.90.20 | — | 96 |
Notes
Only root can lower the nice value (raise priority); unprivileged callers can only raise nice. On macOS, nice() and setpriority() influence the BSD scheduler's tier but not the Mach thread QoS — coexisting QoS classes can dominate scheduling regardless of nice.
Related APIs
getprioritygetrusagegetrlimitsetrlimitproc_rlimit_control