Subj : Re: problem with sem_open
To   : comp.programming.threads
From : David Schwartz
Date : Thu Mar 10 2005 01:46 am


"Mozis" <chokshi.jaydeep@gmail.com> wrote in message 
news:1110445863.440827.78810@o13g2000cwo.googlegroups.com...
> I'm getting segmentation fault with following code:
>
> int
> main ()
> {
> int val;
> sem_t *sem;
> sem = sem_open ("/tmp/testsem1", O_RDWR | O_CREAT, FILE_MODE, 1);
> printf ("sem = %p %x\n",sem,sem);
>
>        sem_getvalue (sem, &val);
> printf ("val = %d\n", val);
> return 0;
> }
>
> O/P : sem = (nil) 0
>        segmentation fault.
>
> I could not figure out what went wrong with the code.plz help me out.
> I'm using RHEL 3 , kenel v2.4.21-8, gcc 3.2.3

    From the man page:

       Upon  successful  completion, the sem_open() function shall return 
the
       address of the semaphore.  Otherwise,  it  shall  return  a  value 
of
       SEM_FAILED  and set errno to indicate the error. The symbol 
SEM_FAILED
       is defined in the <semaphore.h>  header.  No  successful  return 
from
       sem_open() shall return the value SEM_FAILED.

    DS

.