semdelete.c

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#include <xinu.h>

syscall semdelete(sid32 sem)
{
    intmask mask;          /* Saved interrupt mask      */
    struct sentry *semptr; /* Ptr to semaphore table entry  */

    mask = disable();
    if (isbadsem(sem))
    {
        restore(mask);
        return SYSERR;
    }

    semptr = &semtab[sem];
    if (semptr->sstate == S_FREE)
    {
        restore(mask);
        return SYSERR;
    }
    semptr->sstate = S_FREE;

    resched_cntl(DEFER_START);
    while (semptr->scount++ < 0)
    { /* Free all waiting processes */
        ready(getfirst(semptr->squeue));
    }
    resched_cntl(DEFER_STOP);
    restore(mask);
    return OK;
}