What are pthreads and semaphores?

Can you explain what pthreads are?

Pthreads, or POSIX threads, are a standard for multi-threading in C/C++ that allows concurrent execution of code.

What role do semaphores play in pthreads?

Semaphores are synchronization tools used to control access to shared resources in a multi-threaded environment.

How do I implement a semaphore in my pthreads program?

You can use the sem_init, sem_wait, and sem_post functions to create and manage semaphores in your pthreads program.

Can you give me a simple code example?

Sure! Here's a basic example:

#include <pthread.h>
#include <semaphore.h>
#include <stdio.h>

sem_t semaphore;

void* threadFunction(void* arg) {
    sem_wait(&semaphore);
    // Critical section
    printf("Thread %d is in the critical section.\n", *(int*)arg);
    sem_post(&semaphore);
    return NULL;
}

int main() {
    pthread_t threads[5];
    sem_init(&semaphore, 0, 1);
    int threadArgs[5];
    for (int i = 0; i < 5; i++) {
        threadArgs[i] = i;
        pthread_create(&threads[i], NULL, threadFunction, &threadArgs[i]);
    }
    for (int i = 0; i < 5; i++) {
        pthread_join(threads[i], NULL);
    }
    sem_destroy(&semaphore);
    return 0;
}