BSD syscall#254
svc · unix #254
semctl
Performs control operations on a System V semaphore set.
Prototype
int semctl(int semid, int semnum, int cmd, semun_t arg);Returns: int
Arguments
| Name | Type | Dir | Description |
|---|---|---|---|
| semid | int | - | |
| semnum | int | - | |
| cmd | int | - | |
| arg | semun_t | - |
Version history
| XNU tag | macOS | # |
|---|---|---|
| xnu-1456.1.26 | macOS 10.6 Snow Leopard | 254 |
| xnu-1486.2.11 | — | 254 |
| xnu-1504.15.3 | — | 254 |
| xnu-1504.3.12 | — | 254 |
| xnu-1504.7.4 | — | 254 |
| xnu-1504.9.17 | — | 254 |
| xnu-1504.9.26 | — | 254 |
| xnu-1504.9.37 | — | 254 |
Notes
Supports GETVAL, SETVAL, GETALL, SETALL, IPC_STAT, IPC_SET and IPC_RMID. The fourth argument is the classic union semun, which the caller must declare manually because POSIX leaves it to the program. Removal via IPC_RMID wakes every waiter on the set with EIDRM.
Related APIs
semgetsemopipcsipcrm