vxworks 6.x vxTas示例

以下是一个简单的VxWorks 6.x的VxTas示例：

#include <vxWorks.h>
#include <taskLib.h>
#include <stdio.h>

#define TASK_PRIORITY 100
#define TASK_STACK_SIZE 4096

SEM_ID mySem;

void myTask(void) {
    printf("myTask: Waiting for semaphore...\n");
    semTake(mySem, WAIT_FOREVER);
    printf("myTask: Semaphore acquired!\n");
    semGive(mySem);
    printf("myTask: Semaphore released!\n");
}

void myOtherTask(void) {
    printf("myOtherTask: Waiting for semaphore...\n");
    semTake(mySem, WAIT_FOREVER);
    printf("myOtherTask: Semaphore acquired!\n");
    semGive(mySem);
    printf("myOtherTask: Semaphore released!\n");
}

void myThirdTask(void) {
    printf("myThirdTask: Attempting to acquire semaphore...\n");
    int status = semTake(mySem, NO_WAIT);
    if (status == OK) {
        printf("myThirdTask: Semaphore acquired!\n");
        semGive(mySem);
        printf("myThirdTask: Semaphore released!\n");
    } else {
        printf("myThirdTask: Failed to acquire semaphore.\n");
    }
}

int myApp(void) {
    mySem = semBCreate(SEM_Q_PRIORITY, SEM_EMPTY);
    taskSpawn("myTask", TASK_PRIORITY, 0, TASK_STACK_SIZE, (FUNCPTR)myTask, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
    taskSpawn("myOtherTask", TASK_PRIORITY, 0, TASK_STACK_SIZE, (FUNCPTR)myOtherTask, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
    taskSpawn("myThirdTask", TASK_PRIORITY, 0, TASK_STACK_SIZE, (FUNCPTR)myThirdTask, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
    return 0;
}

在这个示例中，我们创建了一个名为“mySem”的二元信号量，并在三个任务中使用它。

`myTask` 和 `myOtherTask` 都尝试获取信号量，然后释放它。`myThirdTask` 尝试获取信号量，但是由于在之前的任务中已经获取了信号量并且还没有释放它，所以它将不能够获取信号量。

要编译和运行此示例，您需要使用VxWorks开发环境。