Re: CreateMutex problem

From:

"Scott McPhillips [MVP]" <org-dot-mvps-at-scottmcp>

Newsgroups:

microsoft.public.vc.language,microsoft.public.win32.programmer.kernel

Date:

Tue, 06 Mar 2007 22:29:17 -0500

Message-ID:

<OPOx$jGYHHA.992@TK2MSFTNGP02.phx.gbl>

Cheng Wu wrote:

Hi Gurus,

I am puzzled by this problem with the CreateMutex API. I cannot use
CreateMutex for a centain type of names with Mutex. For example

#include <windows.h>
#include <stdio.h>

void main()
{
HANDLE m = CreateMutex(NULL, FALSE,
"mmjqtvfj9aanyofk8i2zk1sjtz1dsuebk3bh6sdx6b92ng1x79m0");
if (m)
printf("OK");
else
{
printf("Bad, %d", GetLastError());
}
}

I will always get Bad, 5 (which is access denied accoring to the Win32
error). The problem goes away when I changed the name slightly, like
changing the first character to capital "M". The MSDN does not seem to
explain on the naming of mutex object.

Please advise if you have any ideas on the problem.

Are you trying to share the same mutex between a service and an
application? If so, you cannot pass NULL as the LPSECURITY_ATTRIBUTES
first parameter because apps and services do not share the same security
context.

--
Scott McPhillips [VC++ MVP]