Re: sem_open really strange behavior

[Sergio Sobarzo <ssobarzo at gmail dot com>]

Thanks a lot Andrew,

I read that paragraph thousand of times. However it is not an answer why 
it works if a line is commented or not. I cannot figure an acceptable 
explanation, that's why I thought it will be a gcc question.

On 22-06-2010 9:23, Andrew Bell wrote:
> On Tue, Jun 22, 2010 at 8:16 AM, Sergio Sobarzo<ssobarzo@gmail.com>  wrote:
>    
> > Hi,
> >
> > I'm writing an application using semaphores. Here is a simple code
> > recreating the problem:
> >
> > ***********************************************
> > #include<sys/types.h>
> > #include<stdio.h>
> > #include<semaphore.h>
> > #include<sys/types.h>
> > #include<sys/stat.h>
> > #include<fcntl.h>
> > #include<stdlib.h>
> >
> > int main()
> > {
> >   int ok;
> > //key_t t;
> > char *shm,*s;
> > sem_t *mutex;
> >
> >   mutex = sem_open("/vik",O_CREAT|O_EXCL);
> >   if(mutex == SEM_FAILED)
> >     {
> >       perror("unable to create semaphore");
> >       sem_unlink("vik");
> >       exit(-1);
> >     }
> >
> >   sem_close(mutex);
> >   sem_unlink("vik");
> >   exit(0);
> > }
> > ************************************************
> >      
> The man page for sem_open says that if you include O_CREAT as a flag
> you must also provide the mode and value arguments.  Have you tried
> that?
>
> P.S. - This isn't a gcc issue - you should probably post this to a
> general UNIX programming list.
>
> Best,
>
>