Task之计数信号量示例

/*
 * 公众号  VxWorks567
 */
#include <stdio.h>
#include <wdLib.h>
#include <semLib.h>
#include <taskLib.h>
#include <sysLib.h>

#define TIME_BETWEEN_INTERRUPTS    1   /* 1 tick */
#define TASK_WORK_TIME             2   /* 2 ticks */
#define NUM_OF_GIVES              10   

LOCAL SEM_ID semId;
LOCAL WDOG_ID wdId;

/* synchronizes with interrupts using counting or binary semaphores */
void syncTask()
{
    int eventCount = 0;

    FOREVER
        {
        if(semTake(semId, WAIT_FOREVER) == ERROR)
            {
            printf("syncTask semTake");
            return;
            }

        /* Do "work" */
        taskDelay(TASK_WORK_TIME);
#if 0
        semShow(semId,1);
#endif
        eventCount++;
        printf("semaphore taken %d times\n", eventCount);
        }
    }

/******************************************************************************
 * simulates a hardware device which generates interrupts very quickly and
 * synchronizes with syncTask using semaphores.
 */
void syncISR 
    (
    int times
    )
{
    semGive(semId);
    times--;
    if(times > 0)
        wdStart(wdId, TIME_BETWEEN_INTERRUPTS,(FUNCPTR)syncISR, times);
    }

/******************************************************************************
 * demonstrates task synchronization using counting semaphores.
 * User can also select to use binary semaphore, 
 * for comparision between the two semaphores. 
 */
void testTaskCountingSem 
    (
    char semType /* counting semaphore type 'c' or binary semaphore type 'b' */
    ) 
{
    int syncId;

    switch(semType)
        {
        case 'b':
        case 'B':
            semId = semBCreate(SEM_Q_PRIORITY, SEM_EMPTY);
            break;
        default:
            semId = semCCreate(SEM_Q_PRIORITY, 0);
            break;
        }

    wdId = wdCreate();

    syncId = taskSpawn("tSync",101,0,5000,(FUNCPTR)syncTask,0,0,0,0,0,0,0,0,0,0);

    /* watchdog simulates hardware interrupts */
    wdStart(wdId, TIME_BETWEEN_INTERRUPTS,(FUNCPTR)syncISR, NUM_OF_GIVES); 

    /* arbitrary delay to allow program to complete before clean up */
    taskDelay(sysClkRateGet() + ((TASK_WORK_TIME + 2) * NUM_OF_GIVES));

    taskDelete(syncId);
    semDelete(semId);
    wdDelete(wdId);
    return;
    }