spinlock.cpp

/* spinlock.cpp */
#include <pthread.h>
#include <iostream>

using namespace std;

/* create a mutex lock */
static pthread_spinlock_t echoLock;

void *echoThis(void *text)
{
    /* spin until lock is acquired */
    if(pthread_spin_lock(&echoLock))
    {
        /* error acquiring spin lock */
        /* NOTE: if the lock is already acquired by another thread, then it is not an error, the thread will simply spin until the lock is acquired */
        perror("pthread_spin_lock");
    }

    /* lock was successfully acquired */
    /* ***** START OF CRITICAL SECTION ***** */
    /* print the text */
    cout << "TID: " << pthread_self() << "\t\tTEXT: " << (char *) text << endl << flush;

    /* ***** END OF CRITICAL SECTION ***** */
    /* release the lock */
    if(pthread_spin_unlock(&echoLock))
    {
        /* error releasing lock */
        perror("pthread_spin_unlock");
    }
    /* lock successfully released */
}

int main(int argc, char * argv[])
{
    /* create as many threads as the  number of command line arguments */
    int maxThreads = argc - 1;
    int i;
    pthread_t tid;

    /* initialize the spin lock */
    if(pthread_spin_init(&echoLock, PTHREAD_PROCESS_PRIVATE))
    {
        /* error initializing lock */
        perror("pthread_spin_init");
    }

    /* create threads which will call echoThis */
     for(i = 1; i <= maxThreads; i++)
    {
        /* create a thread with the default properties */
        if(pthread_create(&tid, NULL, echoThis, argv[i]))
        {
            /* error creating thread */
            perror("pthread_create");
        }
    }

    /* wait for all the threads to join */
    while(!pthread_join(tid, NULL))
    {
        /* do nothing */
        ;
    }

    /* destroy the spin lock */
    if(pthread_spin_destroy(&echoLock))
    {
        /* error removing the spin lock */
        perror("pthread_spin_destroy");
    }

    return 0;
}
/* end of spinlock.cpp */