WSACleanup

Synopsis

int WSACleanup(void);

Terminates use of the Winsock DLL (Ws2_32.dll). After calling WSACleanup, no Winsock functions may be called except for another call to WSAStartup.

Return Value

Remarks

• Each successful call to WSAStartup must be balanced by a corresponding call to WSACleanup.
• If an application has multiple threads that have called WSAStartup, WSACleanup must be called an equal number of times before the DLL can be unloaded.
• Calling WSACleanup while sockets are still open will cause those sockets to be closed implicitly.
• This function is thread‑safe.

Example

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

int main(void) {
    WSADATA wsaData;
    if (WSAStartup(MAKEWORD(2,2), &wsaData) != 0) {
        printf("WSAStartup failed\\n");
        return 1;
    }

    // ... use Winsock ...

    int result = WSACleanup();
    if (result == SOCKET_ERROR) {
        printf("WSACleanup failed: %d\\n", WSAGetLastError());
    } else {
        printf("Winsock cleaned up successfully\\n");
    }
    return 0;
}

See Also