[ace-users] ACE_Process_Semaphore vs. ACE_Semaphore(int count, int type = USYNC_PROCESS)

Douglas C. Schmidt schmidt at dre.vanderbilt.edu
Wed Jul 18 16:41:13 CDT 2007

Hi Michael,

> I have the same question for ACE_RW_Process_Mutex vs
> ACE_RW_Mutex(int type=USYNC_PROCESS).

Please use ACE_RW_Thread_Mutex or ACE_RW_Process_Mutex rather than
ACE_RW_Mutex.  Chapter 10 of C++NPv1
<www.cs.wustl.edu/~schmidt/ACE/book1> explains this in more detail.

> Furthermore, there is a note in the source for the former that says
> "Note that because this class uses the <ace_file_lock> as its
> implementation it only can be reliably used between separate
> processes, rather than threads in the same process. This isn't a
> limitation of ACE, it's simply the file lock semantics on UNIX and
> Win32".  Is the same tru for ACE_RW_Mutex(int type=USYNC_PROCESS)?

Please don't use ACE_RW_Mutex unless you are on Solaris.



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