(1) 理解线程和进程的联系和区别；
(2) 掌握Linux下和Windows下创建线程的方法；
(3) 掌握Linux下和Windows下线程同步的方法；
(4) 使用多线程机制实现Linux下和Windows下服务器编程。
(1)Linux下的线程同步
(1.1)编程使用互斥量实现线程同步；
(1.2)编程使用信号量实现线程同步，要求实现以下功能：“线程A从用户输入得到值后存入全局变量num，此时线程B将取走该值并累加。该过程共进行5次，完成后输出总和并退出程序”；
(1.3) 在(1.2)的基础上增加一个线程，用于求和之后计算所有数的平均值。
(1.4)用多线程并发方式实现一个群聊程序，包括服务器端和客户端。
(1.5)利用多线程技术实现回声服务器端，但要让所有线程共享保存客户端消息的内存空间（char数组）。
(2)Windows下的线程同步
(2.1)编程使用临界区对象实现线程同步；
(2.2)编程使用互斥量实现线程同步；
(2.3)编程使用信号量实现线程同步，要求实现以下功能：“线程A从用户输入得到值后存入全局变量num，此时线程B将取走该值并累加。该过程共进行5次，完成后输出总和并退出程序”；
(2.4)在第(2.3)的基础上增加一个线程，用于求和之后计算所有数的平均值。
(2.5)编程使用事件内核对象实现线程同步，要求实现以下功能：分别统计用户输入的字符串中’A’字符和非’A’字符的个数；
(2.6)用多线程并发方式实现一个群聊程序，包括服务器端和客户端。
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <pthread.h>
#define NUM_THREAD 100
void * thread_inc(void * arg);
void * thread_des(void * arg);
long long num=0;
pthread_mutex_t mutex;
int main(int argc, char *argv[])
{
pthread_t thread_id[NUM_THREAD];
int i;
pthread_mutex_init(&mutex, NULL);
for(i=0; i<NUM_THREAD; i++)
{
if(i%2)
pthread_create(&(thread_id[i]), NULL, thread_inc, NULL);
else
pthread_create(&(thread_id[i]), NULL, thread_des, NULL);
}
for(i=0; i<NUM_THREAD; i++)
pthread_join(thread_id[i], NULL);
printf("result: %lld \n", num);
pthread_mutex_destroy(&mutex);
return 0;
}
void * thread_inc(void * arg)
{
int i;
pthread_mutex_lock(&mutex);
for(i=0; i<500; i++)
num+=1;
pthread_mutex_unlock(&mutex);
return NULL;
}
void * thread_des(void * arg)
{
int i;
for(i=0; i<500; i++)
{
pthread_mutex_lock(&mutex);
num-=1;
pthread_mutex_unlock(&mutex);
}
return NULL;
}
测试结果：
//semaphore.c
#include <stdio.h>
#include <pthread.h>
#include <semaphore.h>
void * read(void * arg);
void * accu(void * arg);
static sem_t sem_one;
static sem_t sem_two;
static int num;
int main(int argc, char *argv[])
{
pthread_t id_t1, id_t2;
sem_init(&sem_one, 0, 0);
sem_init(&sem_two, 0, 1);
pthread_create(&id_t1, NULL, read, NULL);
pthread_create(&id_t2, NULL, accu, NULL);
pthread_join(id_t1, NULL);
pthread_join(id_t2, NULL);
sem_destroy(&sem_one);
sem_destroy(&sem_two);
return 0;
}
void * read(void * arg)
{
int i;
for(i=0; i<5; i++)
{
fputs("Input num: ", stdout);
sem_wait(&sem_two);
scanf("%d", &num);
sem_post(&sem_one);
}
return NULL;
}
void * accu(void * arg)
{
int sum=0, i;
for(i=0; i<5; i++)
{
sem_wait(&sem_one);
sum+=num;
sem_post(&sem_two);
}
printf("Result: %d \n", sum);
return NULL;
}
测试结果：
//semaphore1.c
#include <stdio.h>
#include <pthread.h>
#include <semaphore.h>
void * read(void * arg);
void * accu(void * arg);
void * aver(void * arg);
static sem_t sem_one;
static sem_t sem_two;
static sem_t sem_three;
static int num;
static int sum = 0;
int main(int argc, char *argv[])
{
pthread_t id_t1, id_t2, id_t3;
sem_init(&sem_one, 0, 0);
sem_init(&sem_two, 0, 0);
sem_init(&sem_three, 0, 1);
pthread_create(&id_t1, NULL, read, NULL);//读线程
pthread_create(&id_t2, NULL, accu, NULL);//求和线程
pthread_create(&id_t3, NULL, aver, NULL);//求平均值线程
pthread_join(id_t1, NULL);
pthread_join(id_t2, NULL);
pthread_join(id_t3, NULL);
sem_destroy(&sem_one);
sem_destroy(&sem_two);
sem_destroy(&sem_three);
return 0;
}
void * read(void * arg)
{
int i;
for(i=0; i<5; i++)
{
fputs("Input num: ", stdout);
sem_wait(&sem_three);
scanf("%d", &num);
sem_post(&sem_one);
}
return NULL;
}
void * accu(void * arg)
{
int i;
for(i=0; i<5; i++)
{
sem_wait(&sem_one);
sum+=num;
sem_post(&sem_two);
}
printf("Result: %d \n", sum);
return NULL;
}
void * aver(void * arg)
{
int i;
float average=0;
for(i=0; i<5; i++)
{
sem_wait(&sem_two);
average = sum/(i+1);
sem_post(&sem_three);
}
printf("Average: %.2f\n",average);
return NULL;
}
测试结果：
//chat_serv.c
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <pthread.h>
#define BUF_SIZE 100
#define MAX_CLNT 256
void * handle_clnt(void * arg);
void send_msg(char * msg, int len);
void error_handling(char * msg);
int clnt_cnt=0;
int clnt_socks[MAX_CLNT];
pthread_mutex_t mutx;
int main(int argc, char *argv[])
{
int serv_sock, clnt_sock;
struct sockaddr_in serv_adr, clnt_adr;
int clnt_adr_sz;
pthread_t t_id;
if(argc!=2) {
printf("Usage : %s <port>\n", argv[0]);
exit(1);
}
pthread_mutex_init(&mutx, NULL);
serv_sock=socket(PF_INET, SOCK_STREAM, 0);
memset(&serv_adr, 0, sizeof(serv_adr));
serv_adr.sin_family=AF_INET;
serv_adr.sin_addr.s_addr=htonl(INADDR_ANY);
serv_adr.sin_port=htons(atoi(argv[1]));
if(bind(serv_sock, (struct sockaddr*) &serv_adr, sizeof(serv_adr))==-1)
error_handling("bind() error");
if(listen(serv_sock, 5)==-1)
error_handling("listen() error");
while(1)
{
clnt_adr_sz=sizeof(clnt_adr);
clnt_sock=accept(serv_sock, (struct sockaddr*)&clnt_adr,&clnt_adr_sz);
printf("Connected client %d \n", clnt_sock);
pthread_mutex_lock(&mutx);//在临界区中将客户端套接字加入到客户端套接字数组中
clnt_socks[clnt_cnt++]=clnt_sock;
pthread_mutex_unlock(&mutx);
pthread_create(&t_id, NULL, handle_clnt, (void*)&clnt_sock);//创建与该客户端套接字通信的线程
pthread_detach(t_id);//将子线程与主线程分离，子线程结束后，资源自动回收
}
close(serv_sock);
return 0;
}
void * handle_clnt(void * arg)//线程处理函数
{
int clnt_sock=*((int*)arg);
int str_len=0, i;
char msg[BUF_SIZE];
while((str_len=read(clnt_sock, msg, sizeof(msg)))!=0)
send_msg(msg, str_len);
pthread_mutex_lock(&mutx);
for(i=0; i<clnt_cnt; i++) // 移除已断开连接的客户端，此操作在临界区中进行
{
if(clnt_sock==clnt_socks[i])
{
while(i++<clnt_cnt-1)
clnt_socks[i]=clnt_socks[i+1];
break;
}
}
clnt_cnt--;
pthread_mutex_unlock(&mutx);
printf("Connected close: %d \n", clnt_sock);
close(clnt_sock);
return NULL;
}
void send_msg(char * msg, int len) // 向所有已连接的客户端发送消息
{
int i;
pthread_mutex_lock(&mutx);
for(i=0; i<clnt_cnt; i++)
write(clnt_socks[i], msg, len);
pthread_mutex_unlock(&mutx);
}
void error_handling(char * msg)
{
fputs(msg, stderr);
fputc('\n', stderr);
exit(1);
}
//chat_clnt.c
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <pthread.h>
#define BUF_SIZE 100
#define NAME_SIZE 20
void * send_msg(void * arg);
void * recv_msg(void * arg);
void error_handling(char * msg);
char name[NAME_SIZE]="[DEFAULT]";
char msg[BUF_SIZE];
int main(int argc, char *argv[])
{
int sock;
struct sockaddr_in serv_addr;
pthread_t snd_thread, rcv_thread;
void * thread_return;
if(argc!=4) {
printf("Usage : %s <IP> <port> <name>\n", argv[0]);
exit(1);
}
sprintf(name, "[%s]", argv[3]);
sock=socket(PF_INET, SOCK_STREAM, 0);
memset(&serv_addr, 0, sizeof(serv_addr));
serv_addr.sin_family=AF_INET;
serv_addr.sin_addr.s_addr=inet_addr(argv[1]);
serv_addr.sin_port=htons(atoi(argv[2]));
if(connect(sock, (struct sockaddr*)&serv_addr, sizeof(serv_addr))==-1)
error_handling("connect() error");
pthread_create(&snd_thread, NULL, send_msg, (void*)&sock);//发送消息的子线程
pthread_create(&rcv_thread, NULL, recv_msg, (void*)&sock);//接收消息的子线程
pthread_join(snd_thread, &thread_return);//将子线程合入主线程
pthread_join(rcv_thread, &thread_return);
close(sock);
return 0;
}
void * send_msg(void * arg) // send thread main
{
int sock=*((int*)arg);
char name_msg[NAME_SIZE+BUF_SIZE];
while(1)
{
fgets(msg, BUF_SIZE, stdin);
if(!strcmp(msg,"q\n")||!strcmp(msg,"Q\n"))
{
close(sock);
exit(0);
}
sprintf(name_msg,"%s %s", name, msg);
write(sock, name_msg, strlen(name_msg));
}
return NULL;
}
void * recv_msg(void * arg) // read thread main
{
int sock=*((int*)arg);
char name_msg[NAME_SIZE+BUF_SIZE];
int str_len;
while(1)
{
str_len=read(sock, name_msg, NAME_SIZE+BUF_SIZE-1);
if(str_len==-1)
return (void*)-1;
name_msg[str_len]=0;
fputs(name_msg, stdout);
}
return NULL;
}
void error_handling(char *msg)
{
fputs(msg, stderr);
fputc('\n', stderr);
exit(1);
}
测试结果：
//echo_server.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <pthread.h>
#define BUF_SIZE 1024
void error_handling(char *message);
void * handle(void * arg);
void * handle(void * arg);
pthread_mutex_t metux;
char message[BUF_SIZE];
int main(int argc, char *argv[])
{
int serv_sock, clnt_sock;
pthread_t id_t;
struct sockaddr_in serv_adr;
struct sockaddr_in clnt_adr;
socklen_t clnt_adr_sz;
if(argc!=2) {
printf("Usage : %s <port>\n", argv[0]);
exit(1);
}
serv_sock=socket(PF_INET, SOCK_STREAM, 0);
if(serv_sock==-1)
error_handling("socket() error");
pthread_mutex_init(&metux, NULL);
memset(&serv_adr, 0, sizeof(serv_adr));
serv_adr.sin_family=AF_INET;
serv_adr.sin_addr.s_addr=htonl(INADDR_ANY);
serv_adr.sin_port=htons(atoi(argv[1]));
if(bind(serv_sock, (struct sockaddr*)&serv_adr, sizeof(serv_adr))==-1)
error_handling("bind() error");
if(listen(serv_sock, 5)==-1)
error_handling("listen() error");
while(1)
{
clnt_adr_sz=sizeof(clnt_adr);
clnt_sock=accept(serv_sock, (struct sockaddr*)&clnt_adr, &clnt_adr_sz);
if(clnt_sock==-1)
error_handling("accept() error");
else
printf("Connected client %d \n", clnt_sock);
pthread_create(&id_t,NULL,handle,(void*)&clnt_sock);
pthread_detach(id_t);
}
close(serv_sock);
return 0;
}
void * handle(void * arg)
{
int sock=*((int*)arg);
int str_len;
while(1)
{
pthread_mutex_lock(&metux);
str_len=read(sock,message,BUF_SIZE);
if(str_len==0)
break;
else
write(sock,message,str_len);
pthread_mutex_unlock(&metux);
}
printf("close client:%d\n",sock);
close(sock);
return NULL;
}
void error_handling(char *message)
{
fputs(message, stderr);
fputc('\n', stderr);
exit(1);
}
//echo_client.c
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#define BUF_SIZE 1024
void error_handling(char *message);
int main(int argc, char *argv[])
{
int sock;
char message[BUF_SIZE];
int str_len;
struct sockaddr_in serv_adr;
if(argc!=3) {
printf("Usage : %s <IP> <port>\n", argv[0]);
exit(1);
}
sock=socket(PF_INET, SOCK_STREAM, 0);
if(sock==-1)
error_handling("socket() error");
memset(&serv_adr, 0, sizeof(serv_adr));
serv_adr.sin_family=AF_INET;
serv_adr.sin_addr.s_addr=inet_addr(argv[1]);
serv_adr.sin_port=htons(atoi(argv[2]));
if(connect(sock, (struct sockaddr*)&serv_adr, sizeof(serv_adr))==-1)
error_handling("connect() error!");
else
puts("Connected...........");
while(1)
{
fputs("Input message(Q to quit): ", stdout);
fgets(message, BUF_SIZE, stdin);
if(!strcmp(message,"q\n") || !strcmp(message,"Q\n"))
break;
write(sock, message, strlen(message));
str_len=read(sock, message, BUF_SIZE-1);
message[str_len]=0;
printf("Message from server: %s", message);
}
close(sock);
return 0;
}
void error_handling(char *message)
{
fputs(message, stderr);
fputc('\n', stderr);
exit(1);
}
测试结果：
#include <stdio.h>
#include <windows.h>
#include <process.h>
#define NUM_THREAD 2
unsigned WINAPI threadInc(void* arg);
unsigned WINAPI threadDes(void* arg);
long long num = 0;
CRITICAL_SECTION cs;
int main(int argc, char* argv[])
{
HANDLE tHandles[NUM_THREAD];
int i;
InitializeCriticalSection(&cs);//创建CRITICAL_SECTION，相当于临界区的锁
for (i = 0; i < NUM_THREAD; i++)//创建线程
{
if (i % 2)
tHandles[i] = (HANDLE)_beginthreadex(NULL, 0, threadInc, NULL, 0, NULL);
else
tHandles[i] = (HANDLE)_beginthreadex(NULL, 0, threadDes, NULL, 0, NULL);
}
WaitForMultipleObjects(NUM_THREAD, tHandles, TRUE, INFINITE);//对内核对象验证signaled
DeleteCriticalSection(&cs);//销毁
printf("result: %lld \n", num);
return 0;
}
unsigned WINAPI threadInc(void* arg)//加法处理函数
{
int i;
EnterCriticalSection(&cs);//获取，进入临界区
for (i = 0; i < 500; i++)
num += 1;
LeaveCriticalSection(&cs);//释放
return 0;
}
unsigned WINAPI threadDes(void* arg)//减法处理函数
{
int i;
EnterCriticalSection(&cs);
for (i = 0; i < 500; i++)
num -= 1;
LeaveCriticalSection(&cs);
return 0;
}
测试结果：
#include <stdio.h>
#include <windows.h>
#include <process.h>
#define NUM_THREAD 2
unsigned WINAPI threadInc(void* arg);
unsigned WINAPI threadDes(void* arg);
long long num = 0;
HANDLE hMutex;
int main(int argc, char* argv[])
{
HANDLE tHandles[NUM_THREAD];
int i;
hMutex = CreateMutex(NULL, FALSE, NULL);//创建互斥量对象句柄
for (i = 0; i < NUM_THREAD; i++)//创建线程
{
if (i % 2)
tHandles[i] = (HANDLE)_beginthreadex(NULL, 0, threadInc, NULL, 0, NULL);
else
tHandles[i] = (HANDLE)_beginthreadex(NULL, 0, threadDes, NULL, 0, NULL);
}
WaitForMultipleObjects(NUM_THREAD, tHandles, TRUE, INFINITE);//对内核对象验证是否为signaled状态
CloseHandle(hMutex);//销毁内核对象句柄
printf("result: %lld \n", num);
return 0;
}
unsigned WINAPI threadInc(void* arg)//加法处理函数
{
int i;
WaitForSingleObject(hMutex, INFINITE);//临界区的开始
for (i = 0; i < 500; i++)
num += 1;
ReleaseMutex(hMutex);//临界区结束
return 0;
}
unsigned WINAPI threadDes(void* arg)//减法处理函数
{
int i;
WaitForSingleObject(hMutex, INFINITE);
for (i = 0; i < 500; i++)
num -= 1;
ReleaseMutex(hMutex);
return 0;
}
测试结果：
#include <stdio.h>
#include <windows.h>
#include <process.h>
unsigned WINAPI Read(void* arg);
unsigned WINAPI Accu(void* arg);
static HANDLE semOne;
static HANDLE semTwo;
static int num;
int main(int argc, char* argv[])
{
HANDLE hThread1, hThread2;
semOne = CreateSemaphore(NULL, 0, 1, NULL);//创建信号量
semTwo = CreateSemaphore(NULL, 1, 1, NULL);
hThread1 = (HANDLE)_beginthreadex(NULL, 0, Read, NULL, 0, NULL);//创建线程
hThread2 = (HANDLE)_beginthreadex(NULL, 0, Accu, NULL, 0, NULL);
WaitForSingleObject(hThread1, INFINITE);//监听线程是否为signaled状态
WaitForSingleObject(hThread2, INFINITE);
CloseHandle(semOne);//关闭线程
CloseHandle(semTwo);
return 0;
}
unsigned WINAPI Read(void* arg)//加法处理函数
{
int i;
for (i = 0; i < 5; i++)
{
fputs("Input num: ", stdout);
WaitForSingleObject(semTwo, INFINITE);//临界区的开始
scanf("%d", &num);
ReleaseSemaphore(semOne, 1, NULL);//临界区结束
}
return 0;
}
unsigned WINAPI Accu(void* arg)//减法处理函数
{
int sum = 0, i;
for (i = 0; i < 5; i++)
{
WaitForSingleObject(semOne, INFINITE);
sum += num;
ReleaseSemaphore(semTwo, 1, NULL);
}
printf("Result: %d \n", sum);
return 0;
}
测试结果：
#include <stdio.h>
#include <windows.h>
#include <process.h>
unsigned WINAPI Read(void* arg);
unsigned WINAPI Accu(void* arg);
unsigned WINAPI Aver(void* arg);
static HANDLE semOne;
static HANDLE semTwo;
static HANDLE semThree;
static int num;
static int sum = 0;
int main(int argc, char* argv[])
{
HANDLE hThread1, hThread2, hThread3;
semOne = CreateSemaphore(NULL, 0, 1, NULL);
semTwo = CreateSemaphore(NULL, 0, 1, NULL);
semThree = CreateSemaphore(NULL, 1, 1, NULL);
hThread1 = (HANDLE)_beginthreadex(NULL, 0, Read, NULL, 0, NULL);//创建3个线程，分别处理3个函数
hThread2 = (HANDLE)_beginthreadex(NULL, 0, Accu, NULL, 0, NULL);
hThread3 = (HANDLE)_beginthreadex(NULL, 0, Aver, NULL, 0, NULL);
WaitForSingleObject(hThread1, INFINITE);
WaitForSingleObject(hThread2, INFINITE);
WaitForSingleObject(hThread3, INFINITE);
CloseHandle(semOne);
CloseHandle(semTwo);
CloseHandle(semThree);
return 0;
}
unsigned WINAPI Read(void* arg)
{
int i;
for (i = 0; i < 5; i++)
{
fputs("Input num: ", stdout);
WaitForSingleObject(semThree, INFINITE);
scanf("%d", &num);
ReleaseSemaphore(semOne, 1, NULL);
}
return 0;
}
unsigned WINAPI Accu(void* arg)
{
int i;
for (i = 0; i < 5; i++)
{
WaitForSingleObject(semOne, INFINITE);
sum += num;
ReleaseSemaphore(semTwo, 1, NULL);
}
printf("Result: %d \n", sum);
return 0;
}
unsigned WINAPI Aver(void* arg)
{
int i;
float average=0;
for (i = 0; i < 5; i++)
{
WaitForSingleObject(semTwo, INFINITE);
average = (float)sum / (i + 1);
ReleaseSemaphore(semThree, 1, NULL);
}
printf("Average: %.2f \n", average);
return 0;
}
测试结果：
(2.5)编程使用事件内核对象实现线程同步，要求实现以下功能：分别统计用户输入的字符串中’A’字符和非’A’字符的个数；
#include <stdio.h>
#include <windows.h>
#include <process.h>
#define STR_LEN 100
unsigned WINAPI NumberOfA(void* arg);
unsigned WINAPI NumberOfOthers(void* arg);
static char str[STR_LEN];
static HANDLE hEvent;
int main(int argc, char* argv[])
{
HANDLE hThread1, hThread2;
hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);//创建事件的对象句柄
hThread1 = (HANDLE)_beginthreadex(NULL, 0, NumberOfA, NULL, 0, NULL);//创建线程
hThread2 = (HANDLE)_beginthreadex(NULL, 0, NumberOfOthers, NULL, 0, NULL);
fputs("Input string: ", stdout);//输入字符串
fgets(str, STR_LEN, stdin);
SetEvent(hEvent); //将状态改为signaled
WaitForSingleObject(hThread1, INFINITE);
WaitForSingleObject(hThread2, INFINITE);
ResetEvent(hEvent);//将状态改为non-signaled
CloseHandle(hEvent);
return 0;
}
unsigned WINAPI NumberOfA(void* arg)//处理是'A'字符的函数
{
int i, cnt = 0;
WaitForSingleObject(hEvent, INFINITE);//等待signaled状态
for (i = 0; str[i] != 0; i++)
{
if (str[i] == 'A')
cnt++;
}
printf("Num of A: %d \n", cnt);
return 0;
}
unsigned WINAPI NumberOfOthers(void* arg)//处理不是'A'字符的函数
{
int i, cnt = 0;
WaitForSingleObject(hEvent, INFINITE);
for (i = 0; str[i] != 0; i++)
{
if (str[i] != 'A')
cnt++;
}
printf("Num of others: %d \n", cnt - 1);
return 0;
}
测试结果：
服务端：
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <windows.h>
#include <process.h>
#define BUF_SIZE 100
#define MAX_CLNT 256
unsigned WINAPI HandleClnt(void* arg);
void SendMsg(char* msg, int len);
void ErrorHandling(char* msg);
int clntCnt = 0;
SOCKET clntSocks[MAX_CLNT];
HANDLE hMutex;
int main(int argc, char* argv[])
{
WSADATA wsaData;
SOCKET hServSock, hClntSock;
SOCKADDR_IN servAdr, clntAdr;
int clntAdrSz;
HANDLE hThread;
if (argc != 2) {
printf("Usage : %s <port>\n", argv[0]);
exit(1);
}
if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
ErrorHandling("WSAStartup() error!");
hMutex = CreateMutex(NULL, FALSE, NULL);//创建互斥量对象
hServSock = socket(PF_INET, SOCK_STREAM, 0);
memset(&servAdr, 0, sizeof(servAdr));
servAdr.sin_family = AF_INET;
servAdr.sin_addr.s_addr = htonl(INADDR_ANY);
servAdr.sin_port = htons(atoi(argv[1]));
if (bind(hServSock, (SOCKADDR*)&servAdr, sizeof(servAdr)) == SOCKET_ERROR)
ErrorHandling("bind() error");
if (listen(hServSock, 5) == SOCKET_ERROR)
ErrorHandling("listen() error");
while (1)
{
clntAdrSz = sizeof(clntAdr);
hClntSock = accept(hServSock, (SOCKADDR*)&clntAdr, &clntAdrSz);
WaitForSingleObject(hMutex, INFINITE);//等待进入临界区
clntSocks[clntCnt++] = hClntSock;//将刚连接的客户端套接字加入到套接字数组中
ReleaseMutex(hMutex);//退出临界区
hThread =
(HANDLE)_beginthreadex(NULL, 0, HandleClnt, (void*)&hClntSock, 0, NULL);//创建线程
printf("Connected client IP: %s \n", inet_ntoa(clntAdr.sin_addr));
}
closesocket(hServSock);
WSACleanup();
return 0;
}
unsigned WINAPI HandleClnt(void* arg)//处理函数
{
SOCKET hClntSock = *((SOCKET*)arg);
int strLen = 0, i;
char msg[BUF_SIZE];
while ((strLen = recv(hClntSock, msg, sizeof(msg), 0)) != 0)
SendMsg(msg, strLen);//向所有已存在的客户端发送消息
WaitForSingleObject(hMutex, INFINITE);//进入临界区将关闭的套接字移除
for (i = 0; i < clntCnt; i++) // remove disconnected client
{
if (hClntSock == clntSocks[i])
{
while (i++ < clntCnt - 1)
clntSocks[i] = clntSocks[i + 1];
break;
}
}
clntCnt--;
ReleaseMutex(hMutex);
closesocket(hClntSock);
return 0;
}
void SendMsg(char* msg, int len) // send to all发送消息处理函数
{
int i;
WaitForSingleObject(hMutex, INFINITE);//进入临界区向客户端发送消息
for (i = 0; i < clntCnt; i++)
send(clntSocks[i], msg, len, 0);
ReleaseMutex(hMutex);
}
void ErrorHandling(char* msg)
{
fputs(msg, stderr);
fputc('\n', stderr);
exit(1);
}
客户端：
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <windows.h>
#include <process.h>
#define BUF_SIZE 100
#define NAME_SIZE 20
unsigned WINAPI SendMsg(void* arg);
unsigned WINAPI RecvMsg(void* arg);
void ErrorHandling(char* msg);
char name[NAME_SIZE] = "[DEFAULT]";
char msg[BUF_SIZE];
int main(int argc, char* argv[])
{
WSADATA wsaData;
SOCKET hSock;
SOCKADDR_IN servAdr;
HANDLE hSndThread, hRcvThread;
if (argc != 4) {
printf("Usage : %s <IP> <port> <name>\n", argv[0]);
exit(1);
}
if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
ErrorHandling("WSAStartup() error!");
sprintf(name, "[%s]", argv[3]);//客户端姓名
hSock = socket(PF_INET, SOCK_STREAM, 0);
memset(&servAdr, 0, sizeof(servAdr));
servAdr.sin_family = AF_INET;
servAdr.sin_addr.s_addr = inet_addr(argv[1]);
servAdr.sin_port = htons(atoi(argv[2]));
if (connect(hSock, (SOCKADDR*)&servAdr, sizeof(servAdr)) == SOCKET_ERROR)
ErrorHandling("connect() error");
hSndThread =
(HANDLE)_beginthreadex(NULL, 0, SendMsg, (void*)&hSock, 0, NULL);//创建发送消息的线程
hRcvThread =
(HANDLE)_beginthreadex(NULL, 0, RecvMsg, (void*)&hSock, 0, NULL);//创建接收消息的线程
WaitForSingleObject(hSndThread, INFINITE);
WaitForSingleObject(hRcvThread, INFINITE);
closesocket(hSock);
WSACleanup();
return 0;
}
unsigned WINAPI SendMsg(void* arg) // send thread main发送
{
SOCKET hSock = *((SOCKET*)arg);
char nameMsg[NAME_SIZE + BUF_SIZE];
while (1)
{
fgets(msg, BUF_SIZE, stdin);
if (!strcmp(msg, "q\n") || !strcmp(msg, "Q\n"))
{
closesocket(hSock);
exit(0);
}
sprintf(nameMsg, "%s %s", name, msg);
send(hSock, nameMsg, strlen(nameMsg), 0);
}
return 0;
}
unsigned WINAPI RecvMsg(void* arg) // read thread main接收
{
int hSock = *((SOCKET*)arg);
char nameMsg[NAME_SIZE + BUF_SIZE];
int strLen;
while (1)
{
strLen = recv(hSock, nameMsg, NAME_SIZE + BUF_SIZE - 1, 0);
if (strLen == -1)
return -1;
nameMsg[strLen] = 0;
fputs(nameMsg, stdout);
}
return 0;
}
void ErrorHandling(char* msg)
{
fputs(msg, stderr);
fputc('\n', stderr);
exit(1);
}
测试结果：
其中对于1.3，需要创建3个信号量，在线程对临界变量进行访问的时候，各信号量的值需要设置好。先读取数据，求和，再求平均数。这样就不会使多个线程对临界区同时操作。
对于1.5，由于存储消息的字符串数组设定成一个共享变量，在某个客户端通信时，其他客户端只能够等待，等该客户端通信完毕释放临界区后，其他客户端才能够与服务器通信。
Windows线程同步比linux线程同步更复杂一点，windows下分为内核模式与用户模式，两种模式工作模式不同。其中，在内核模式的同步中，除了基于互斥量与信号量对象的同步外，还有基于事件对象的同步，对比前两种，该同步方法有很大的不同。
Linux下和Windows的线程对比后，有相同点与不同点，需要结合操作系统下线程同步的原理加以理解与运用。