/*********************************************************************************
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* Copyright: (C) 2025 LingYun IoT System Studio
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* All rights reserved.
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*
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* Filename: thread.c
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* Description: This file is thread example program
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*
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* Version: 1.0.0(11/04/2025)
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* Author: Guo Wenxue <guowenxue@gmail.com>
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* ChangeLog: 1, Release initial version on "11/04/2025 02:26:44 PM"
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*
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********************************************************************************/
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#include <stdio.h>
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#include <string.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <pthread.h>
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typedef struct worker_ctx_s
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{
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int shared_var;
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pthread_mutex_t lock1; /* lock for thread1 */
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pthread_mutex_t lock2; /* lock for thread2 */
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} worker_ctx_t;
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void *thread_worker1(void *args);
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void *thread_worker2(void *args);
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int main(int argc, char **argv)
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{
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pthread_t tid;
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pthread_attr_t thread_attr;
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worker_ctx_t worker_ctx;
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/* initial worker_ctx and lock */
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worker_ctx.shared_var = 1000;
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pthread_mutex_init(&worker_ctx.lock1, NULL);
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pthread_mutex_init(&worker_ctx.lock2, NULL);
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/* lock thread2, let threa1 run first */
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pthread_mutex_lock(&worker_ctx.lock2);
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if( pthread_attr_init(&thread_attr) )
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{
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printf("pthread_attr_init() failure: %s\n", strerror(errno));
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return -1;
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}
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if( pthread_attr_setstacksize(&thread_attr, 120*1024) )
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{
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printf("pthread_attr_setstacksize() failure: %s\n", strerror(errno));
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return -1;
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}
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if( pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED) )
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{
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printf("pthread_attr_setdetachstate() failure: %s\n", strerror(errno));
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return -1;
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}
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pthread_create(&tid, &thread_attr, thread_worker1, &worker_ctx);
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printf("Thread worker1 tid[%ld] created ok\n", tid);
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pthread_create(&tid, NULL, thread_worker2, &worker_ctx);
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printf("Thread worker2 tid[%ld] created ok\n", tid);
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pthread_attr_destroy(&thread_attr);
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printf("Main/Control thread shared_var: %d\n", worker_ctx.shared_var);
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/* Wait until thread worker2 exit() */
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pthread_join(tid, NULL);
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while(1)
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{
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sleep(10);
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}
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/* destroy mutex lock */
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pthread_mutex_destroy(&worker_ctx.lock1);
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pthread_mutex_destroy(&worker_ctx.lock2);
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return 0;
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}
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void *thread_worker1(void *args)
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{
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worker_ctx_t *ctx = (worker_ctx_t *)args;
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if( !args )
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{
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printf("%s() get invalid arguments\n", __FUNCTION__);
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pthread_exit(NULL);
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}
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printf("Thread1 [%ld] start running...\n", pthread_self());
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while(1)
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{
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/* wait for thread1 lock */
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pthread_mutex_lock(&ctx->lock1);
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printf("+++: Thread1 before seelp shared_var: %d\n", ctx->shared_var);
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ctx->shared_var ++;
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sleep(2);
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printf("+++: Thread1 after seelp shared_var: %d\n", ctx->shared_var);
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/* release thread2 lock */
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pthread_mutex_unlock(&ctx->lock2);
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}
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printf("Thread1 exit...\n");
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return NULL;
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}
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void *thread_worker2(void *args)
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{
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worker_ctx_t *ctx = (worker_ctx_t *)args;
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if( !args )
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{
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printf("%s() get invalid arguments\n", __FUNCTION__);
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pthread_exit(NULL);
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}
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printf("Thread2 [%ld] start running...\n", pthread_self());
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while(1)
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{
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/* wait for thread2 lock */
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if(0 != pthread_mutex_trylock(&ctx->lock2) )
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{
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continue; /* lock is busy */
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}
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printf("---: Thread2 before seelp shared_var: %d\n", ctx->shared_var);
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ctx->shared_var ++;
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sleep(2);
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printf("---: Thread2 after seelp shared_var: %d\n", ctx->shared_var);
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/* release thread1 lock */
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pthread_mutex_unlock(&ctx->lock1);
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}
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printf("Thread2 exit...\n");
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return NULL;
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}
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