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Creating a Basic Winsock Application

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To create a basic Winsock application

  1. Create a new empty project.

  2. Add an empty C++ source file to the project.

  3. Ensure that the build environment refers to the Include, Lib, and Src directories of the Microsoft Windows Software Development Kit (SDK) or the earlier Platform Software Development Kit (SDK).

  4. Ensure that the build environment links to the Winsock Library file Ws2_32.lib. Applications that use Winsock must be linked with the Ws2_32.lib library file. The #pragma comment indicates to the linker that the Ws2_32.lib file is needed.

  5. Begin programming the Winsock application. Use the Winsock API by including the Winsock 2 header files. The Winsock2.h header file contains most of the Winsock functions, structures, and definitions. The Ws2tcpip.h header file contains definitions introduced in the WinSock 2 Protocol-Specific Annex document for TCP/IP that includes newer functions and structures used to retrieve IP addresses.

    Note

    Stdio.h is used for standard input and output, specifically the printf() function.

     

#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdio.h>

#pragma comment(lib, "Ws2_32.lib")

int main() {
  return 0;
}

Note

The Iphlpapi.h header file is required if an application is using the IP Helper APIs. When the Iphlpapi.h header file is required, the #include line for the Winsock2.h header file should be placed before the #include line for the Iphlpapi.h header file.

The Winsock2.h header file internally includes core elements from the Windows.h header file, so there is not usually an #include line for the Windows.h header file in Winsock applications. If an #include line is needed for the Windows.h header file, this should be preceded with the #define WIN32_LEAN_AND_MEAN macro. For historical reasons, the Windows.h header defaults to including the Winsock.h header file for Windows Sockets 1.1. The declarations in the Winsock.h header file will conflict with the declarations in the Winsock2.h header file required by Windows Sockets 2.0. The WIN32_LEAN_AND_MEAN macro prevents the Winsock.h from being included by the Windows.h header. An example illustrating this is shown below.

 

#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN
#endif

#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <iphlpapi.h>
#include <stdio.h>

#pragma comment(lib, "Ws2_32.lib")

int main() {
  return 0;
}

Next Step: Initializing Winsock

Getting Started With Winsock

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