|SEMGET(2)||System Calls Manual||SEMGET(2)|
semget — obtain a
int nsems, int semflg);
Based on the values of key and
returns the identifier of a newly created or previously existing set of
semaphores. The key is analogous to a filename: it provides a handle that
names an IPC object. There are three ways to specify a key:
The mode of a newly created IPC object is determined by OR'ing the following constants into the semflg argument:
If a new set of semaphores is being created, nsems is used to indicate the number of semaphores the set should contain. Otherwise, nsems may be specified as 0.
semget() system call returns the id of
a semaphore set if successful; otherwise, -1 is returned and
errno is set to indicate the error.
semget() system call will fail if:
|September 12, 1995||macOS 14.1|