Debugging in the Command Line with dbx

Listing 1 Sample source code to be debugged

#include <stdio.h>
#include <pthread.h>
#include <stdlib.h>
#include <unistd.h>

pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
int             iCounter = 0;

void
incrementCounter()
{
    /*
     * Increment iCounter by 1 using an inconsistent state protected by
     * the mutex
     */
    pthread_mutex_lock(&mutex);
    iCounter += 9999;
    iCounter -= 9998;
    pthread_mutex_unlock(&mutex);
    usleep(200);
}

void           *
myThread(void *arg)
{
    /* Unused argument */
    arg;

    while (1)
        incrementCounter();

}

int
main()
{
    pthread_t       tid = 0;
    int             i = 0;
    char           *pLeak = NULL;

    /* Hereunder is a small memory leak */
    pLeak = malloc(100);

    /* Create a thread */
    pthread_create(&tid, NULL, myThread, NULL);

    /*
     * Display the counter value when the mutex is acquired every 500 ms
     * until it reaches 100
     */
    while (i < 100) {
        pthread_mutex_lock(&mutex);
        printf("iCounter=%d\n", i = iCounter);
        pthread_mutex_unlock(&mutex);
        usleep(500);
    }

    /* Cancel the computing worker thread */
    pthread_cancel(tid);

    return 0;
}