What are read-write locks in the pthreads library?

Can you explain what read-write locks are in the pthreads library?

Read-write locks allow multiple threads to read shared data simultaneously while ensuring exclusive access for writing.

How do read-write locks improve performance compared to regular mutexes?

They improve performance by allowing concurrent reads, which is beneficial when reads are more frequent than writes.

Can you show me a simple code example of using read-write locks?

Sure! Here's a basic example:

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

pthread_rwlock_t lock;

void* reader(void* arg) {
    pthread_rwlock_rdlock(&lock);
    // Read data
    pthread_rwlock_unlock(&lock);
}

void* writer(void* arg) {
    pthread_rwlock_wrlock(&lock);
    // Write data
    pthread_rwlock_unlock(&lock);
}

This code demonstrates how to lock for reading and writing.

What happens if a writer tries to acquire the lock while readers are active?

The writer will be blocked until all active readers release the lock, ensuring data consistency.