缓冲区设计—线程间通讯(C语言程序实现)

有没有接触过C++的朋友看到上篇文章，希望给出C程序的实现。

匆忙之中没有以通用的的函数形式给出，而是将缓冲区代码与测试代码混合一个源程序，程序也写得丑陋了一些，仅供朋友们学习实现的原理。程序在linux 环境下已测试通过。

 

 

 # include <limits.h># include <pthread.h># include <stdlib.h># include <stdio.h> # define MAXNTHREADS 100# define NBUFF 20 typedef struct { pthread_cond_t cond; int resource;} Cond; typedef struct { pthread_t id; int seq;} Data; Cond getCond = { PTHREAD_COND_INITIALIZER, 0 };Cond putCond = { PTHREAD_COND_INITIALIZER, NBUFF };pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; Data buff[NBUFF];int front = 0;int rear = 0;int size = 0; int run = 1; void stop(){ run = 0;  pthread_mutex_lock(&mutex);  getCond.resource = INT_MAX / 2; pthread_cond_broadcast(&getCond.cond); putCond.resource = INT_MAX / 2; pthread_cond_broadcast(&putCond.cond);  pthread_mutex_unlock(&mutex);} intput(const Data* data){ pthread_mutex_lock(&mutex);  while( putCond.resource < 1 ) pthread_cond_wait(&putCond.cond, &mutex); putCond.resource--;  if ( run ) { buff[rear] = *data; rear = (rear + 1) / NBUFF; size++; }  getCond.resource++; pthread_cond_signal(&getCond.cond); pthread_mutex_unlock(&mutex); return run;} intget(Data* data){ int rc;  pthread_mutex_lock(&mutex);  while( getCond.resource < 1 ) pthread_cond_wait(&getCond.cond, &mutex); getCond.resource--;  if ( size != 0 ) {/* not empty */ *data = buff[front]; front = (front + 1) % NBUFF; size--;  rc = 1; } else rc = 0;  putCond.resource++; pthread_cond_signal(&putCond.cond); pthread_mutex_unlock(&mutex);  return rc;} int nitems, nputs, ngets; void *put_thread(void *arg){ Data data;  data.id = pthread_self();  for ( data.seq = 0; data.seq < nitems; data.seq++ ) { put(&data); *((int *)arg) += 1; }  return 0;} void *get_thread(void *arg){ pthread_t tid; Data data;  tid = pthread_self();  while( get(&data) ) { printf("%lu %lu %d/n", tid, data.id, data.seq); *((int *)arg) += 1; }  return 0;} intmain(int argc, char **argv){ int i, p, g; int putcount[MAXNTHREADS], getcount[MAXNTHREADS]; pthread_t tid_put[MAXNTHREADS], tid_get[MAXNTHREADS];  if ( argc < 4 ) { fprintf(stderr, "Usage: %s <#items> <#put> <#get>/n", argv[0]); return -1; }  nitems = atoi(argv[1]); nputs = atoi(argv[2]);  if ( nputs > MAXNTHREADS ) nputs = MAXNTHREADS;  ngets = atoi(argv[3]);  if ( ngets > MAXNTHREADS ) ngets = MAXNTHREADS;  printf("Item: <%d> Puts: <%d> Gets: <%d>/n", nitems, nputs, ngets);  for ( i = 0; i < nputs; i++ ) { putcount[i] = 0; pthread_create(&tid_put[i], 0, put_thread, &putcount[i]); }  for ( i = 0; i < ngets; i++ ) { getcount[i] = 0; pthread_create(&tid_get[i], 0, get_thread, &getcount[i]); }  p = 0; for ( i = 0; i < nputs; i++ ) { pthread_join(tid_put[i], 0); printf("Put %lu count[%d] = %d/n", tid_put[i], i, putcount[i]); p += putcount[i]; }  stop();  g = 0; for ( i = 0; i < ngets; i++ ) { pthread_join(tid_get[i], 0); g += getcount[i]; printf("Get %lu count[%d] = %d/n", tid_get[i], i, getcount[i]); }  printf("Get %d Put %d/n", g, p);  return 0;}