c - 我如何在c中多线程这个TCP服务器/客户端？

Question

我如何在c中多线程这个TCP服务器/客户端？请帮助我多线程处理此代码，以便我可以同时使用多个客户端。我如何应用线程以及在哪里应用？

TCP 服务器

#include <stdio.h>   
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <errno.h>
#include <signal.h>
#include <unistd.h>
#include <string.h>
//#include <arpa/innet.h> // inet -> innet !Error!
#include <arpa/inet.h>
#include <sys/wait.h>

int main (void)
{
// Declare and define    
int ls;                         // Listen socket descriptor (reference)
int s;                          // socket descriptor (reference)
char buffer [256];              // Data buffer
char* ptr = buffer;             // Data buffer
int len = 0;                        // Number of bytes to send or receive
int maxLen = sizeof (buffer);       // Maximum number of bytes to receive
int n = 0;                      // Number of bytes for each recv call
int waitSize = 16;                  // Size of waiting clients
struct sockaddr_in serverAddr;      // Server address
struct sockaddr_in clientAddr;      // Client address
//int clntAddrLen;                  // Length of client address

struct sockaddr_in servAddr; // !ADDED!
int SERV_PORT = 49999; // !ADDED!



// Create listen socketd
//if (ls = socket (PF_INET, SOCK_STREAM, 0) < 0);
ls = socket (AF_INET, SOCK_STREAM, 0);
if (ls < 0)
{
    perror ("Error: Listen socket failed!");
    exit (1);
}

// Create local (server) socket address
//memset (&servAddr, 0, sizeof (servAddr));
memset(&servAddr, '0', sizeof(servAddr));
servAddr.sin_family = AF_INET;
//servAddr.sin_addr.s_addr = htonl (INADDR_ANY);        // Default IP address
servAddr.sin_addr.s_addr = INADDR_ANY;      // Default IP address
servAddr.sin_port = htons (SERV_PORT);          // Default port
memset( &( servAddr.sin_zero ), '\0', 8 );

// Bind listen socket to the local socket address
//if (bind (ls, &servAddr, sizeof (servAddr)) < 0);
if (bind (ls, ( struct sockaddr * ) &servAddr, sizeof (servAddr)) < 0)
{
    perror ("Error: binding failed!");
    exit (1);
}

// Listen to connection requests
//if (listen (ls, waitSize) < 0);
if (listen (ls, waitSize) < 0)
{
    perror ("Error: listening failed!");
    exit (1);
}

struct sockaddr_in clntAddr; // !ADD!
socklen_t clntAddrLen = sizeof(clntAddr); // !ADD!
//int clntAddrLen = sizeof(clntAddr); // !ADD!

// Handle the connection
for ( ; ; )     // Run forever
{
    printf("for ( ; ; )\n");
    // Accept connections from client
    //if (s = accept (ls, &clntAddr, &clntAddrLen) < 0);
    if ((s = accept (ls, (struct sockaddr *)&clntAddr, &clntAddrLen)) < 0)
    {
        //perror ("Error: accepting failed!);
        perror ("Error: accepting failed!");
        exit (1);
    }
    printf("accept\n");

    // Data transfer section
    if(( n = recv( s, buffer, sizeof( buffer ), 0 ) ) <= 0 )
    {
        perror("recv");
    }
    else
    {
        printf("Recv %d byte \n", n);
    }
    /*
    while ((n = recv (s, ptr, maxLen, 0)) > 0)
    {
        //ptr + = n;            // Move pointer along the buffer
        ptr += n;           // Move pointer along the buffer
        //maxLen - = n;     // Adjust maximum number of bytes to receive
        maxLen -= n;        // Adjust maximum number of bytes to receive
        //len + = n;            // Update number of bytes received
        len += n;           // Update number of bytes received
    }
    */
    int dataSend=0;
    //dataSend = send (s, buffer, len, 0);      // Send back (echo) all bytes received
    dataSend = send (s, buffer, n, 0);      // Send back (echo) all bytes received
    if(dataSend==-1)
    {
        printf("dataSend==-1 \n");
        perror("send");
    }
    else
    {
        printf("Send %d byte \n", dataSend);
    }

    // Close the socket
    close (s);                                   
} // End of for loop

} // End of echo server program

TCP 客户端

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <errno.h>
#include <signal.h>
#include <unistd.h>
#include <string.h>
//#include <arpa/innet.h> // inet -> innet !Error!
#include <arpa/inet.h>
#include <sys/wait.h>

int main (int argc, char* argv[  ])     // Three arguments to be checked later
{
// Declare and define    
int s;                      // Socket descriptor
int  n;                     // Number of bytes in each recv call
char* servName;             // Server name
int servPort;                   // Server port number
char* string;                   // String to be echoed
int len;                        // Length of string to be echoed
char buffer [256 + 1];          // Buffer
char* ptr = buffer;         // Pointer to move along the buffer
struct sockaddr_in serverAddr;  // Server socket address
int maxLen = 256; // !ADD!

// Check and set arguments    
//if (argc != 3)
if (argc != 4)
{                                              
    printf ("Error: three arguments are needed!");                           
    exit (1);
}                  
//servName = arg[1]; // !Error!
servName = argv[1];
//servPort = atoi(arg [2]); // !Error!
servPort = atoi(argv[2]);
//string = arg [3]; // !Error!
string = argv[3];

struct sockaddr_in servAddr; // !ADD!


/*c
// Create socket
//if((s = socket (PF_INET, SOCK_STREAM, 0) < 0);
s = socket(AF_INET, SOCK_STREAM, 0);
if(s < 0)
{
    perror ("Error: socket creation failed!");
    exit (1);
}
bd/*

// Create remote (server) socket address
//memset (&servAddr, 0, sizeof(servAddr));
memset (&servAddr, '0', sizeof(servAddr));
serverAddr.sin_family = AF_INET;
inet_pton (AF_INET, servName, &serverAddr.sin_addr); // Server IP address
serverAddr.sin_port = htons (servPort);     // Server port number
*/
// Create socket
if((s = socket(AF_INET, SOCK_STREAM, 0)) < 0)
{
    printf("\n Error : Could not create socket \n");
    return 1;
}
/**/
// Create remote (server) socket address
memset(&servAddr, '0', sizeof(servAddr));
servAddr.sin_family = AF_INET;
servAddr.sin_port = htons(servPort);

if(inet_pton(AF_INET, argv[1], &servAddr.sin_addr)<=0)
{
    printf("\n inet_pton error occured\n");
    return 1;
}

// Connect  to the server
if( connect(s, (struct sockaddr *)&servAddr, sizeof(servAddr)) < 0)
{
    perror ("Error: connection failed!");
    exit (1);
}

// Connect  to the server
//if (connect (sd, (struct sockaddr*)&servAddr, sizeof(servAddr)) < 0);
/*  if (connect (s, (struct sockaddr*)&servAddr, sizeof(servAddr)) < 0)
{

    perror ("Error: connection failed!");
    exit (1);
}
*/
printf("connect\n");
int dataSend=0;
// Data transfer section
//send (s, string, strlen(string), 0);
dataSend = send (s, string, strlen(string), 0);
//dataSend = send (s, "123", 4, 0);
if(dataSend==-1)
{
    printf("dataSend==-1 \n");
    perror("send");
}
else
{
    printf("else \n");
}
printf("while \n");

if(( n = recv( s, buffer, sizeof( buffer ), 0 ) ) <= 0 )
{
    perror("recv");
}
else
{
    printf("Recv %d byte \n", n);
}

/*
while ((n = recv (s, ptr, maxLen, 0)) > 0)  
{ 
    //ptr + = n;        // Move pointer along the buffer
    ptr += n;       // Move pointer along the buffer
    //maxLen - = n; // Adjust the maximum number of bytes
    maxLen -= n;    // Adjust the maximum number of bytes
    len += n;       // Update the length of string received
    printf("while1 \n");
} // End of while loop  
*/

// Print and verify the echoed string
//buffer [len] = Â’\0Â’;
buffer [n] = '\0';
printf ("Echoed string received: \n");
fputs (buffer, stdout);
printf ("\n");

// Close socket
close (s);

// Stop program
exit (0);

} // End of echo client program

Answer 1

要使服务器多线程化，请在接受连接后立即调用

pthread_create();

为了管理另一个线程中的连接。看看这个post in SO 。应该会有帮助。