01-29-2009
Can't the process itself remember when its used a semaphore before? Sems don't have that kind of memory, they're just counters and a queue. I've written and deleted many solutions here, realizing partway through that they all fail when a process can't remember how many times its locked it already.
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LEARN ABOUT OSF1
sem_unlink
sem_unlink(3) Library Functions Manual sem_unlink(3)
NAME
sem_unlink - Removes the specified named semaphore (P1003.1b)
LIBRARY
Realtime Library (librt.so, librt.a)
SYNOPSIS
#include <semaphore.h>
int sem_unlink (
const char *name) ;
PARAMETERS
*name Specifies the name of the semaphore to remove.
DESCRIPTION
The sem_unlink function removes a semaphore named by the string name. If the semaphore is referenced by other processes, sem_unlink does
not change the state of the semaphore.
If other processes have the semaphore open when sem_unlink is called, the semaphore is not destroyed until all references to the semaphore
have been destroyed by calls to sem_close. The sem_unlink function returns immediately; it does not wait until all references have been
destroyed.
Calls to sem_open to recreate or reconnect to the semaphore refer to a new semaphore after sem_unlink is called.
RETURN VALUES
On a successful call, a value of 0 (zero) is returned. Otherwise, a value of -1 is returned and errno is set to indicate that an error
occurred.
ERRORS
The sem_unlink function fails under the following conditions:
[EACCES] Permission is denied to unlink the named semaphore.
[ENAMETOOLONG] The length of the name string exceeds {NAME_MAX} while {_POSIX_NO_TRUNC} is in effect.
[ENOENT] The named semaphore does not exist.
RELATED INFORMATION
Functions: sem_close(3), sem_open(3)
Guide to Realtime Programming delim off
sem_unlink(3)