This is the mail archive of the cygwin mailing list for the Cygwin project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [Fwd: [ sem_* functions in cygwin]]

Gerrit P. Haase wrote:
Corinna Vinschen wrote:

[Catching up on some older mails]

----- Forwarded message from "Gerrit P. Haase" -----
From: "Gerrit P. Haase" To: cygwin ML
Subject: sem_* functions in cygwin
Date: Sun, 21 Nov 2004 22:48:20 +0100


nearly all sem_* functions are available, but sem_unlock is missing,
was there a problem implementing sem_unlock() or was it just missed
by accident?

Gerrit ----- End forwarded message -----

I guess you're asking about sem_unlink(). It's not implemented so far
since named POSIX semaphores are implemented using named Windows semaphores. The SUSv3 description contains a pretty unfortunate implementation detail:

  Calls to sem_open() to recreate or reconnect to the semaphore refer
  to a new semaphore after sem_unlink() is called.

There's no way I know of, which allows to implement this using named
Windows semaphores.  At least not without adding a lot of annoying
bookkeeping overhead, possibly involving cygserver.

I got an undefined reference to sem_unlock().

I don't remember now which package it was, however there is a maro used in linux which is based on ipc_unlock(): #define sem_unlock(id) ipc_unlock(&sem_ids,id)

Gerrit -- =^..^=

Unsubscribe info:
Problem reports:

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]