December 1998
Beginner to intermediate
674 pages
40h 41m
English
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Name
semctl
Synopsis
semctl id, semnum, cmd, arg
Description
Calls the System V IPC system call semctl(2). If
cmd is &IPC_STAT or &GETALL, then arg must
be a variable
which will hold the returned semid_ds structure or semaphore
value array. The function returns like ioctl: the undefined
value for error, 0 but true for zero, or the actual return
value otherwise. On error, it puts the error code into $!.
Before calling, you should say:
require "ipc.ph"; require "sem.ph";
This function is available only on machines supporting System V IPC.
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.