Given with the threads the program must print the thread based on their priorities starting from 0 to 10.
Thread is lightweight process that runs inside a program. A simple program can contain n number of threads.
Unlike java, multithreading is not supported by the language standards, POSIX Threads (Pthreads) is the standard used in multithreading in C/C++. C does not contain any built-in support for multithreaded applications. Instead, it relies entirely upon the operating system to provide this feature.
To use the thread functions we use header file #include. This header file will include all the functions related to thread in our program like pthread_create(), etc.
Now the task is to synchronize n number of threads using pthread standard library present with gcc compiler. The idea is take thread count and print 1 in first thread, print 2 in second thread, print 3 in third thread till 10th thread. The output will contain numbers from 1 to 10 based upon the priorities of the threads.
Start Step 1 -> Declare global variables as int MAX=10 and count=1 Step 2 -> declare variable thr of pthread_mutex_t and cond of pthread_cond_t Step 3 -> Declare Function void *even(void *arg) Loop While(count < MAX) Call pthread_mutex_lock(&thr) Loop While(count % 2 != 0) Call pthread_cond_wait(&cond, &thr) End Print count++ Call pthread_mutex_unlock(&thr) Call pthread_cond_signal(&cond) End Call pthread_exit(0) Step 4 -> Declare Function void *odd(void *arg) Loop While(count < MAX) Call pthread_mutex_lock(&thr) Loop While(count % 2 != 1) Call pthread_cond_wait(&cond, &thr) End Print count++ Call pthread_mutex_unlock(&thr) Call pthread_cond_signal(&cond) End Set pthread_exit(0) Step 5 -> In main() Create pthread_t thread1 and pthread_t thread2 Call pthread_mutex_init(&thr, 0) Call pthread_cond_init(&cond, 0) Call pthread_create(&thread1, 0, &even, NULL) Call pthread_create(&thread2, 0, &odd, NULL) Call pthread_join(thread1, 0) Call pthread_join(thread2, 0) Call pthread_mutex_destroy(&thr) Call pthread_cond_destroy(&cond) Stop
#include <pthread.h> #include <stdio.h> #include <stdlib.h> int MAX = 10; int count = 1; pthread_mutex_t thr; pthread_cond_t cond; void *even(void *arg){ while(count < MAX) { pthread_mutex_lock(&thr); while(count % 2 != 0) { pthread_cond_wait(&cond, &thr); } printf("%d ", count++); pthread_mutex_unlock(&thr); pthread_cond_signal(&cond); } pthread_exit(0); } void *odd(void *arg){ while(count < MAX) { pthread_mutex_lock(&thr); while(count % 2 != 1) { pthread_cond_wait(&cond, &thr); } printf("%d ", count++); pthread_mutex_unlock(&thr); pthread_cond_signal(&cond); } pthread_exit(0); } int main(){ pthread_t thread1; pthread_t thread2; pthread_mutex_init(&thr, 0); pthread_cond_init(&cond, 0); pthread_create(&thread1, 0, &even, NULL); pthread_create(&thread2, 0, &odd, NULL); pthread_join(thread1, 0); pthread_join(thread2, 0); pthread_mutex_destroy(&thr); pthread_cond_destroy(&cond); return 0; }
if we run above program then it will generate following output
1 2 3 4 5 6 7 8 9 10