D3Codex
UNIX

s command

.md

The s command displays or changes the semaphore status.

Syntax

s [*|sem]{[?|+|-]}

Parameter(s)

sem Specifies the semaphore expressed from 0 to 4.
* Specifies all semaphores.
+ Sets or locks the specified semaphore.
- Unlocks the specified semaphore.
? Displays: 
00: O pid=0985
01: O pib=0023
02:
03: O pib=001A
where

  • semaphore 0 is owned by the process with the PID number of x'0985'. Only semaphore 0 displays with the UNIX PID number instead of the D3 PIB number

  • semaphore 1 is busy, owned by the PIB x'23' and has at least one process waiting on it (W).

  • semaphore 2 is free.

  • semaphore 3 is busy, owned by process x'1A' but has no process waiting on it.

If the owner PIB is not setup when the command is executed, the message pib=? displays. Re-enter the command again to set the owner PIB.