Example ofsynchronizationthrough binarysemaphore

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#include "vxWorks.h"
#include "semLib.h"
#define T_PRIORITY 50

SEM_ID syncExampleSem;    // named semaphore object
void initialize (void)
{
    // set up FIFO queue with emtpy binary semaphore
   
syncSem = semBCreate (SEM_Q_FIFO, SEM_EMPTY);
    // create task1
    taskSpawn ("task1", T_PRIORITY, 0, 10000, task1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
    // create task2
    taskSpawn ("task2", T_PRIORITY, 0, 10000, task2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
}
void task1 (void)
{
    // stay here until semaphore becomes available
    semTake (syncExampleSem, WAIT_FOREVER);

    // do something
}

void task2 (void)
{
    // do something


    // now let task1 execute
    semGive (synExampleSem);
}
Example ofresource lockoutthrough mutualexclusionsemaphore
#include "vxWorks.h"
#include "semLib.h"
#define T_HI_PRIORITY 20
#define T_LO_PRIORITY 200
SEM_ID semMutex;    // named semaphore object
char alphabet[27]; // memory resource to have exclusive access
void initialize (void)
{

//create binary semaphore which is initially full
  semMutex = semBCreate (SEM_Q_PRIORITY, SEM_FULL);
    // spawn high priority task
    taskSpawn ("hi_priority_task", T_HI_PRIORITY, 10000, tHiPriorityTask, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
    // spawn low priority task
    taskSpawn ("lo_priority_task", T_LO_PRIORITY, 10000, tLoPriorityTask, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
void tHiPriorityTask (void)
{
   int i;
    // enter critical region - any other tasks wanting access to alphabet[] should
    // wait for available semaphore
    semTake (semMutex, WAIT_FOREVER);
    // write alphabet to global array
    for(i=0;i<26; i++)
        alphabet = 'A' + i;
    alphabet = '\0';
    // leave critical region
    semGive (semMutex);
}
void tLoPriorityTask (void)
{
    // enter critical region
    semTake (semMutex, WAIT_FOREVER);
    // array members guaranteed stable while being
    printf ("alphabet= %s ", alphabet);
    // leave critical region
    semGive (semMutex);
}