首先是从main函数开发：

int main(itn argc,char* argv[])
{
pthread_t thread;
int count;
int status;
        client_threads = CLIENT_THREADS;
for(count = 0;count <client_threads,count++)
{
status = pthread_create(&thread,NULL,client_routine,(void*)count);
if(status != 0)
err_abort(status,"Create client thread");
}
status = pthread_mutex_lock(&client_mutex);
if(status != 0)
err_abort(status,"Lock client mutex");
while(client_threads>0)
{
status = pthread_cond_wait(&clients_done,&client_mutex);
if(status != 0)
err_abort(status,"Wait for client to finish");
}
status = pthread_mutex_unlock(&client_mutex);
if(status != 0)
err_abort(status,"Unlock client mutex");
printf("All client done\n");
tty_server_request(REQ_QUIT,1,NULL,NULL);
return 0;
}

这个main函数在中间for循环中，调用pthread_create函数创建4个线程，传递给线程的数据位count(0,1,2,3).调用client_routine函数。

void *client_routine(void *arg)
{
int my_number = (int)arg,loops;
char prompt[32];
char string[128],formatted[128];
int status;
sprintf(prompt,"Client 5d>",my_number);
while(1)
{
tty_server_request(REQ_READ,1,prompt,string);
if(strlen(string) ==0)
break;
for(loops =0;loops <4;loops++)
{
sprintf(formatted,"(%d#%d)%s",my_number,loops,string);
tty_server_request(REQ_WRITE,0,NULL,formatted);
sleep(1);
}
}
status = pthread_mutex_lock(&client_mutex);
if(status != 0)
err_abort(status,"Lock client mutex");
client_threads--;
if(client_threads <= 0)
{
status = pthread_cond_signal(&clients_done);
if(status != 0)
err_abort(status,"Signale client done");
}
status = pthread_mutex_unlock(7client_mutex);
if(status != 0)
err_abort(status,"Unlock client mutex");
return NULL;
}

在这里如果没有线程，则通知等待创建线程唤醒wait在此条件变量上的等待。

上面全部代码：

#include <pthread.h>
#include <math.h>
#include "errors.h"


#define CLIENT_THREADS 4


#define REQ_READ 1
#define REQ_WRITE 2
#define REQ_QUIT 3


typedef struct request_tag
{
struct request_tag *next;
int operation;
int synchronous;
int done_flag;
pthread_cond_t done;
char prompt[32];
char text[128];
}request_t;


typedef struct tty_server_tag
{
request_t *first;
request_t *last;
int running;
pthread_mutex_t mutex;
pthread_cond_t request;
}tty_server_t;


tty_server_t tty_server = 
{
NULL,NULL,0,PTHREAD_MUTEX_INITIALIZER,PTHREAD_COND_INITIALIZER
};


int client_threads;
pthread_mutex_t client_mutex = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t clients_done = PTHREAD_COND_INITIALIZER;


void *tty_server_routine(void *arg)
{
static pthread_mutex_t prompt_mutex = PTHREAD_MUTEX_INITIALIZER;
request_t *request;
int operation,len;
int status;
while(1)
{
status = pthread_mutex_lock(&tty_server.mutex);
if(status != 0)
err_abort(status,"Lock server mutex");
while(tty_server.first ==NULL)
{
status = pthread_cond_wait(&tty_server.request,&tty_server.mutex);
if(status != 0)
{
err_abort(status,"Wait for request");
}
request = tty_server.first;
tty_server.first= request->next;
if(tty_server.first == NULL)
{
tty_server.last = NULL;
}
status = pthread_mutex_unlock(&tty_server.mutex);
if(status != 0)
err_abrort(status,"Unlock server mutex");
operation = request->operation;
switch(operation)
{
case REQ_QUIT:
break;
case REQ_READ:
if(strlen(request->prompt)>0)
printf(request->prompt);
if(fgets(request->text,128,stdin)==NULL)
request->text[0]=‘\0‘;
len = strlen(request->text);
if(len>0&&request->text[len-1]==‘\n‘)
request->text[len-1]=‘\0‘;
break;
case REQ_WRITE:
puts(request->text);
break;
default:
break;
}
if(request->synchronous)
{
status = pthread_mutex_lock(&tty_server.mutex);
if(status != 0)
err_abort(status,"Lock server mutex");
request->done_flag =1;
status = pthread_cond__signal(&request->done);
if(status != 0)
err_abort(status,"Unlock server mutex");
}else
free(request);
if(operation ==REQ_QUIT)
break;
}
return NULL;
}


void tty_server_request(int operation,int sync,const char* prompt,char* string)
{
request_t *request;
int status;


status =pthread_mutex_lock(&tty_server.mutex);
if(status != 0)
err_abort(status,"Lock server mutex");
if(!tty_server.running)
{
pthread_t thread;
pthread_attr_t detached_attr;


status = pthread_attr_init(&detached_attr);
if(status != 0)
err_abort(status,"Init attributes object");
status = pthread_attr_setdetachstate(&detached_attr,PTHREAD_CREATE_DETACHED);
if(status != 0)
err_abort(status,"Set detach state");
tty_server.running = 1;
status = pthread_create(&thread,&detached_attr,tty_server_routine,NULL);
if(status != 0)
err_abort(status,"Create server");
pthread_attr_destroy(&detached_attr);
}
request = (request_t*)malloc(sizeof(request_t));
if(request ==NULL)
errno_abort("Allocate Request");
request->next = NULL;
request->operation = operation;
request->synchronous = sync;
if(sync)
{
request->done_flag = 0;
status = pthread_cond_init(&request->done,NULL);
if(status != 0)
err_abort(status ,"Init request condition");
}
if(prompt != NULL)
strncpy(request->prompt,prompt,32);
else 
request->prompt[0]=‘\0‘;
if(operation == REQ_WRITE &&string != NULL)
strncpy(request->text,string,128);
else
request->text[0]=‘\0‘;
if(tty_server.first == NULL)
{
tty_server.first = request;
tty_server.last = request;
}else
{
(tty_server.last)->next = request;
tty_server.last= request;
}
status = pthread_cond_signal(&tty_server.request);
if(status != 0)
err_abort(status,"Wake server");
if(sync)
{
while(!request->done_flag)
{
status = pthread_cond_wait(&request->done,&tty_server.mutex);
if(status != 0)
err_abort(status,"Wait for sync request");
}
if(operation == REQ_READ)
{
if(strlen(request->text)>0)
strcpy(string,request->text);
else 
string[0]=‘\0‘;
}
status = pthread_cond_destroy(&request->done);
if(status != 0)
err_abort(status,"destroy request condition");
free(request);
}
status = pthread_mutex_unlock(&tty-server.mutex);
if(status != 0)
err_abort(status,"Unlock mutex");
}

客户端、服务器端编程