/*
* Initialize a backend-local latch.
*/
void
InitLatch(volatile Latch *latch)
{
/* Initialize the self-pipe if this is our first latch in the process */
if (selfpipe_readfd == -1)
initSelfPipe();
latch->is_set = false;
latch->owner_pid = MyProcPid;
latch->is_shared = false;
}
/*
* Associate a shared latch with the current process, allowing it to
* wait on it.
*
* Make sure that latch_sigusr1_handler() is called from the SIGUSR1 signal
* handler, as shared latches use SIGUSR1 to for inter-process communication.
*/
void
OwnLatch(volatile Latch *latch)
{
Assert(latch->is_shared);
/* Initialize the self pipe if this is our first latch in the process */
if (selfpipe_readfd == -1)
initSelfPipe();
/* sanity check */
if (latch->owner_pid != 0)
elog(ERROR, "latch already owned");
latch->owner_pid = MyProcPid;
}
