I can't open an existing semaphore

Asked Nov 23 '17 at 17:17

Active Nov 24 '17 at 05:45

Viewed 1,140 times

I have defined as #define SNAME "/mysem" on my two programs. On the first I am creating the semaphore as

sem_t *sem = sem_open(SNAME, O_CREAT, 0644, 1);

The second process is creating by the first and I am trying to open the existing semaphore as

sem_t *sem = sem_open(SNAME,0);

The two returning addresses are different though. Any help?

edited Nov 24 '17 at 05:45

tripleee

asked Nov 23 '17 at 17:17

Greg Kalantzis

Post a https://stackoverflow.com/help/mcve – Robert Nov 23 '17 at 20:40
There's no reason for the addresses to be the same. Two separate programs, two different virtual address spaces, etc. The pointer returned simply points to an opaque data structure. That structure is not shared by separate programs – bazza Nov 24 '17 at 06:29
1

It works, indeed... Thanks! – Greg Kalantzis Nov 24 '17 at 13:59
No worries, good luck! – bazza Nov 24 '17 at 20:42

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