轉貼 VxWorks thread同步(使用Semaphore)

/* includes */
#include "vxWorks.h"
#include "taskLib.h"
#include "semLib.h"
#include "stdio.h"

/* function prototypes */
void taskOne(void);
void taskTwo(void);

/* globals */
#define ITER 10
SEM_ID semBinary;
int global = 0;

void binary(void)
{
int taskIdOne, taskIdTwo;

/* create semaphore with semaphore available and queue tasks on FIFO basis */
semBinary = semBCreate(SEM_Q_FIFO, SEM_FULL);

/* Note 1: lock the semaphore for scheduling purposes */
semTake(semBinary,WAIT_FOREVER);

/* spawn the two tasks */
taskIdOne = taskSpawn("t1",90,0x100,2000,(FUNCPTR)taskOne,0,0,0,0,0,0,0,0,0,0);
taskIdTwo = taskSpawn("t2",90,0x100,2000,(FUNCPTR)taskTwo,0,0,0,0,0,0,0,0,0,0);
}


void taskOne(void)
{
int i;
for (i=0; i < ITER; i++)
 {
 semTake(semBinary,WAIT_FOREVER); /* wait indefinitely for semaphore */
 printf("I am taskOne and global = %d......................\n", ++global);
 semGive(semBinary); /* give up semaphore */
 } 
}

void taskTwo(void)
{
int i;
semGive(semBinary); /* Note 2: give up semaphore(a scheduling fix) */
for (i=0; i < ITER; i++)
 {
 semTake(semBinary,WAIT_FOREVER); /* wait indefinitely for semaphore */
 printf("I am taskTwo and global = %d----------------------\n", --global);
 semGive(semBinary); /* give up semaphore */
 } 
}