Question

How to create TCP client server socket communication on windows in C

Answer 1

/*
You need to link the library: libws2_32.a 
OR
-lwsock32
-lws2_32
from c:\TDM-GCC-64\x86_64-w64-mingw32\lib32\
OR
c:\MinGW\lib\
if you using GCC on windows
*/
  
// Client and Server are on the same computer, with different exe files and two console windows 

// TCP Server program

#include <stdio.h>
#include <WinSock2.h>

int main() {
    printf("TCP SERVER\n");

    WSADATA Winsockdata;
    SOCKET TCPServerSocket;
    struct sockaddr_in TCPServerAddr;
    struct sockaddr_in TCPClientAddr;
    int TCPClientAddrSize = sizeof(TCPClientAddr);
    SOCKET AcceptSocket;
    char SendBuffer[512] = "Hello from Server!";
    char RecvBuffer[512];

    // STEP-1 WSAStartUp
    if (WSAStartup(MAKEWORD(2,2), &Winsockdata) != 0) {
        printf("SERVER: WSAStartUp Failed");
    }
    printf("SERVER: WSAStartUp Success\n");

    // STEP-2 Fill TCPServerAddr Struct
    TCPServerAddr.sin_family = AF_INET;
    TCPServerAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
    TCPServerAddr.sin_port = htons(8888);

    //STEP-3 Create Socket
    if ((TCPServerSocket = socket(AF_INET,SOCK_STREAM,IPPROTO_TCP)) == INVALID_SOCKET) {
        printf("SERVER: TCP Server: Create Socket Failed, Error: %d\n", WSAGetLastError());
    }
    printf("SERVER: TCP Server: Create Socket Success\n");

    //STEP-4 bind
    if (bind(TCPServerSocket, (SOCKADDR*)&TCPServerAddr, sizeof(TCPServerAddr)) == SOCKET_ERROR) {
        printf("SERVER: Binding Failed, Error: %d", WSAGetLastError());
    }
    printf("SERVER: Binding Success\n");

    //STEP-5 Listen
    if (listen(TCPServerSocket, 2) == SOCKET_ERROR) {
        printf("SERVER: Listen Failed, Error: %d", WSAGetLastError());
    }
    printf("SERVER: Listen Success: Listening for incoming connection...\n");

    // STEP-6 Accept
    if ((AcceptSocket = accept(TCPServerSocket, (SOCKADDR *)&TCPClientAddr, &TCPClientAddrSize)) == INVALID_SOCKET) {
        printf("SERVER: Accept Failed, Error: %d\n", WSAGetLastError());
    }
    printf("SERVER: Connection Accepted\n");

    // STEP-7 Send Message to Client
    if (send(AcceptSocket,SendBuffer, sizeof(SendBuffer), 0) == SOCKET_ERROR) {
        printf("SERVER: Send Failed Error: %d\n", WSAGetLastError());
    }
    printf("SERVER: Message Sent!\n");

    // STEP-8 Recv Message from Client
    if (recv(AcceptSocket,RecvBuffer, sizeof(RecvBuffer), 0) == SOCKET_ERROR) {
        printf("SERVER: Receive Failed, Error: %d\n", WSAGetLastError());
    }
    printf("SERVER: Received Message From Client: %s\n", RecvBuffer);

    // STEP-9 Close Socket
    if (closesocket(TCPServerSocket) == SOCKET_ERROR) {
        printf("SERVER: Close Socket Failed, Error: %d\n", WSAGetLastError());
    }
    printf("SERVER: Close Socket Success\n");

    // STEP-10 Clean
    if (WSACleanup() == SOCKET_ERROR) {
        printf("SERVER: WSACleanup Failed, Error: %d\n", WSAGetLastError());
    }
    printf("SERVER: WSACleanup Success\n");

    return 0;
}




/*
run:

TCP SERVER
SERVER: WSAStartUp Success
SERVER: TCP Server: Create Socket Success
SERVER: Binding Success
SERVER: Listen Success: Listening for incoming connection...
SERVER: Connection Accepted
SERVER: Message Sent!
SERVER: Received Message From Client: Hello from Client!
SERVER: Close Socket Success
SERVER: WSACleanup Success

*/

// TCP Client program

#include <stdio.h>
#include <WinSock2.h>

int main() {
    printf("TCP CLIENT\n");

    WSADATA WinSockData;

    SOCKET TCPClientSocket;
    struct sockaddr_in TCPServerAddr;
    char RecvBuffer[512];
    char SendBuffer[512] = "Hello from Client!";

    //STEP-1 WSASatrtUp
    if (WSAStartup(MAKEWORD(2,2),&WinSockData) != 0) {
        printf("CLIENT: WSAStartUp Failed\n");
    }
    printf("CLIENT: WSAStartUp Success\n");

    // STEP-2 Create Socket
    if ((TCPClientSocket = socket(AF_INET,SOCK_STREAM,IPPROTO_TCP)) == INVALID_SOCKET) {
        printf("CLIENT: TCP Client: Create Socket Failed, Error: %d\n", WSAGetLastError());
    }
    printf("CLIENT: TCP Client: Create Socket Success\n");

    // STEP-3 Fill TCPServerAddr
    TCPServerAddr.sin_family = AF_INET;
    TCPServerAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
    TCPServerAddr.sin_port = htons(8888);

    // STEP-4 Connect to Server
    if (connect(TCPClientSocket, (SOCKADDR *)&TCPServerAddr, sizeof(TCPServerAddr)) == SOCKET_ERROR) {
    //if (iConnect == SOCKET_ERROR) {
       printf("CLIENT: Connection Failed, Error: %d\n", WSAGetLastError());
    }
    printf("CLIENT: Connection Success\n");

    // STEP-5 Recv Message From Server
    if (recv(TCPClientSocket, RecvBuffer, sizeof(RecvBuffer), 0) == SOCKET_ERROR) {
        printf("CLIENT: Receive Message Failed, Error: %d\n", WSAGetLastError());
    }
    printf("CLIENT: Received Message From Server: %s\n", RecvBuffer);

    // STEP-6 Send Message to Server
    if (send(TCPClientSocket,SendBuffer,sizeof(SendBuffer),0) == SOCKET_ERROR) {
        printf("CLIENT: Send Failed, Error: %d\n", WSAGetLastError());
    }
    printf("CLIENT: Message Sent!\n");

    // STEP-7 Close Socket
    if (closesocket(TCPClientSocket) == SOCKET_ERROR) {
        printf("CLIENT: Close Socket Failed, Error: %d\n", WSAGetLastError());
    }
    printf("CLIENT: Close Socket Success\n");

    // STEP-8 Clean
    if (WSACleanup() == SOCKET_ERROR){
        printf("CLIENT: WSACleanup Failed, Error: %d\n", WSAGetLastError());
    }
    printf("CLIENT: WSACleanup Success\n");

    return 0;
}




/*
run:

TCP CLIENT
CLIENT: WSAStartUp Success
CLIENT: TCP Client: Create Socket Success
CLIENT: Connection Success
CLIENT: Received Message From Server: Hello from Server!
CLIENT: Message Sent!
CLIENT: Close Socket Success
CLIENT: WSACleanup Success

*/

 

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