十个线程写作打印4个文件的C代码实现

打印要求：

建立10个线程，编号为0~9，分别打印4个文件A.txt，B.txt，C.txt，D.txt
每个文件要求打印100行内容，以/r/n作为行分隔符。
其中，A.txt的内容如下：
Thread 1 print
Thread 2 print
Thread 3 print
Thread 4 print
Thread 5 print
Thread 6 print
Thread 7 print
Thread 8 print
Thread 9 print
Thread 0 print
Thread 1 print
Thread 2 print
Thread 3 print
...
Thread 0 print

B.txt的内容如下：
Thread 0 print
Thread 9 print
Thread 8 print
Thread 7 print
Thread 6 print
Thread 5 print
Thread 4 print
Thread 3 print
Thread 2 print
Thread 1 print
Thread 0 print
Thread 9 print
Thread 8 print
...
Thread 1 print

C.txt的内容如下：
Thread 1 print
Thread 3 print
Thread 5 print
Thread 7 print
Thread 9 print
Thread 1 print
Thread 3 print
...
Thread 9 print

D.txt的内容如下：
Thread 2 print
Thread 4 print
Thread 6 print
Thread 8 print
Thread 0 print
Thread 2 print
Thread 4 print
...
Thread 0 print

 

代码实现

编写过程中，遇到的主要问题是信号丢失问题。

后来用了定时锁定，过了时间后自动解除阻塞，程序继续运行。

可以避免线程之间下入死锁的局面。

#include <stdio.h> #include <pthread.h> #include <time.h> #include <sys/timeb.h> #define MAX_LINE_NUM 10000 pthread_t thread[10]; pthread_mutex_t thread_mutex[10]; pthread_cond_t condition[10]; int print_queue[10][4]; pthread_mutex_t file_a_mutex; pthread_mutex_t file_b_mutex; pthread_mutex_t file_c_mutex; pthread_mutex_t file_d_mutex; int file_a_thread_no; int file_b_thread_no; int file_c_thread_no; int file_d_thread_no; int print_a_times = 0; int print_b_times = 0; int print_c_times = 0; int print_d_times = 0; FILE *file_a_writer; FILE *file_b_writer; FILE *file_c_writer; FILE *file_d_writer; void *print_file(void *p_t_index) { int thread_index = *(int *)p_t_index; int file_a_over = 0; int file_b_over = 0; int file_c_over = 0; int file_d_over = 0; int block_ret_status; struct timespec block_end_time; printf("Thread [%d] create/n", thread_index); while(1) { printf("Thread [%d] wait for lock/n", thread_index); pthread_mutex_lock(&thread_mutex[thread_index]); block_end_time.tv_sec = time(NULL) + 1; block_end_time.tv_nsec = 0; printf("Thread [%d] wait for condition/n", thread_index); block_ret_status = pthread_cond_timedwait(&condition[thread_index], &thread_mutex[thread_index], &block_end_time); if(block_ret_status == 0) { printf("Thread [%d] get condition/n", thread_index); } else { printf("Thread [%d] wait for condition timeout/n", thread_index); } /*****************************print A.txt*****************************************/ //printf("Thread [%d] try lock,A/n", thread_index); if(0 == pthread_mutex_trylock(&file_a_mutex)) { //printf("Thread [%d] get lock,print no[%d],A/n", thread_index, file_a_thread_no); if(MAX_LINE_NUM <= print_a_times) { file_a_over = 1; } else { if(thread_index == file_a_thread_no) { fprintf(file_a_writer, "Thread [%d] print A/r/n", thread_index); fflush(file_a_writer); file_a_thread_no = (file_a_thread_no + 1) % 10; //printf("Thread [%d] print A,signal thead[%d]/r/n", thread_index, file_a_thread_no); print_a_times++; } } } //sleep(1); printf("Signal thread[%d],A/r/n", file_a_thread_no); pthread_cond_signal(&condition[file_a_thread_no]); pthread_mutex_unlock(&file_a_mutex); /*****************************print B.txt*****************************************/ //printf("Thread [%d] try lock,B/n", thread_index); if(0 == pthread_mutex_trylock(&file_b_mutex)) { //printf("Thread [%d] get lock,print no[%d],A/n", thread_index, file_b_thread_no); if(MAX_LINE_NUM <= print_b_times) { file_b_over = 1; } else { if(thread_index == file_b_thread_no) { fprintf(file_b_writer, "Thread [%d] print B/r/n", thread_index); fflush(file_b_writer); file_b_thread_no = (file_b_thread_no + 10 - 1) % 10; //printf("Thread [%d] print B,signal thead[%d]/r/n", thread_index, file_b_thread_no); print_b_times++; } } } //sleep(1); printf("Signal thread[%d],B/r/n", file_b_thread_no); pthread_cond_signal(&condition[file_b_thread_no]); pthread_mutex_unlock(&file_b_mutex); /*****************************print C.txt*****************************************/ //printf("Thread [%d] try lock,C/n", thread_index); if(0 == pthread_mutex_trylock(&file_c_mutex)) { //printf("Thread [%d] get lock,print no[%d],C/n", thread_index, file_c_thread_no); if(MAX_LINE_NUM <= print_c_times) { file_c_over = 1; } else { if(thread_index == file_c_thread_no) { fprintf(file_c_writer, "Thread [%d] print C/r/n", thread_index); fflush(file_c_writer); file_c_thread_no = (file_c_thread_no + 2) % 10; //printf("Thread [%d] print C,signal thead[%d]/r/n", thread_index, file_c_thread_no); print_c_times++; } } } //sleep(1); printf("Signal thread[%d],C/r/n", file_c_thread_no); pthread_cond_signal(&condition[file_c_thread_no]); pthread_mutex_unlock(&file_c_mutex); /*****************************print D.txt*****************************************/ //printf("Thread [%d] try lock,D/n", thread_index); if(0 == pthread_mutex_trylock(&file_d_mutex)) { //printf("Thread [%d] get lock,print no[%d],D/n", thread_index, file_d_thread_no); if(MAX_LINE_NUM <= print_d_times) { file_d_over = 1; } else { if(thread_index == file_d_thread_no) { fprintf(file_d_writer, "Thread [%d] print D/r/n", thread_index); fflush(file_d_writer); file_d_thread_no = (file_d_thread_no + 2) % 10; //printf("Thread [%d] print D,signal thead[%d]/r/n", thread_index, file_d_thread_no); print_d_times++; } } } //sleep(1); printf("Signal thread[%d],D/r/n", file_d_thread_no); pthread_cond_signal(&condition[file_d_thread_no]); pthread_mutex_unlock(&file_d_mutex); printf("Thread [%d] unlock/n", thread_index); pthread_mutex_unlock(&thread_mutex[thread_index]); if(file_a_over && file_b_over && file_c_over && file_d_over) { int index = 0; for(;index < 10;index++) { pthread_cond_signal(&condition[index]); } printf("Thread [%d] exit/n", thread_index); pthread_exit(NULL); } } } int main() { int thread_index = 0; struct timeb begin_time_p; struct tm *begin_time_m; struct timeb end_time_p; struct tm *end_time_m; file_a_writer = fopen("A.txt", "ab+"); file_b_writer = fopen("B.txt", "ab+"); file_c_writer = fopen("C.txt", "ab+"); file_d_writer = fopen("D.txt", "ab+"); ftime(&begin_time_p); begin_time_m = localtime(&(begin_time_p.time)); pthread_mutex_init(&file_a_mutex, NULL); pthread_mutex_init(&file_b_mutex, NULL); pthread_mutex_init(&file_c_mutex, NULL); pthread_mutex_init(&file_d_mutex, NULL); file_a_thread_no = 1; file_b_thread_no = 0; file_c_thread_no = 1; file_d_thread_no = 2; for(thread_index = 0; thread_index < 10; thread_index++) { pthread_attr_t tattr; int thread_init_res = 0; pthread_attr_setschedpolicy(&tattr, SCHED_RR); thread_init_res = pthread_create(&thread[thread_index], &tattr, print_file, (void *)&thread_index); pthread_cond_init(&condition[thread_index], NULL); pthread_mutex_init(&thread_mutex[thread_index], NULL); } printf("before thread condition signal!/n"); pthread_cond_signal(&condition[0]); pthread_cond_signal(&condition[1]); pthread_cond_signal(&condition[1]); pthread_cond_signal(&condition[2]); for(thread_index = 0; thread_index < 10; thread_index++) { pthread_join(thread[thread_index], NULL); } ftime(&end_time_p); end_time_m = localtime(&(end_time_p.time)); printf("Time Cost[%4d-%2d-%2d %2d:%2d:%2d:%2d]/n", end_time_m->tm_year - begin_time_m->tm_year, end_time_m->tm_mon - begin_time_m->tm_mon, end_time_m->tm_mday - begin_time_m->tm_mday, end_time_m->tm_hour - begin_time_m->tm_hour, end_time_m->tm_min - begin_time_m->tm_min, end_time_m->tm_sec - begin_time_m->tm_sec); getchar(); return 0; }