Creates or opens a named semaphore with the specified name.
Syntax
#include <pripcsem.h> #define PR_SEM_CREATE 0x1 /* create if not exist */ #define PR_SEM_EXCL 0x2 /* fail if already exists */ NSPR_API(PRSem *) PR_OpenSemaphore( const char *name, PRIntn flags, PRIntn mode, PRUintn value );
Parameters
The function has the following parameters:
name- The name to be given the semaphore.
flags- How to create or open the semaphore.
mode- Unix style file mode to be used when creating the semaphore.
value- The initial value assigned to the semaphore.
Returns
A pointer to a PRSem structure or NULL/code> on error.
Description
If the named semaphore doesn't exist and the PR_SEM_CREATE flag is specified, the named semaphore is created. The created semaphore needs to be removed from the system with a PR_DeleteSemaphore call.
If PR_SEM_CREATE is specified, the third argument is the access permission bits of the new semaphore (same interpretation as the mode argument to PR_Open) and the fourth argument is the initial value of the new semaphore. If PR_SEM_CREATE is not specified, the third and fourth arguments are ignored.