[Overview][Constants][Types][Procedures and functions][Index] | Reference for unit 'ipc' (#rtl)

# semget

Return the ID of a semaphore set, possibly creating the set

## Declaration

Source position: ipc.pp line 872

`function semget(`
`key: TKey;`
`nsems: cint;`
`semflg: cint`
`):cint;`

## Description

msgget returns the ID of the semaphore set described by key. Depending on the flags in semflg, a new queue is created.

semflg can have one or more of the following values (combined by ORs):

IPC_CREAT
  The queue is created if it doesn't already exist.
IPC_EXCL
  If used in combination with IPC_CREAT, causes the call to fail if the set already exists. It cannot be used by itself.

Optionally, the flags can be ORed with a permission mode, which is the same mode that can be used in the file system.

if a new set of semaphores is created, then there will be nsems semaphores in it.

## Errors

On error, -1 is returned, and IPCError is set.

## See also

ftok |  | Create token from filename
semop |  | Perform semaphore operation.
semctl |  | Perform various control operations on a semaphore set