ioctlsocket 函数返回值

ioctlsocket函数的返回值是一个整数。如果函数调用成功，它将返回0。如果函数调用失败，它将返回SOCKET_ERROR错误，并且应用程序可以通过调用WSAGetLastError()函数来获取相应的错误代码。

范例：ioctlsocket函数返回值的示例代码如下所示：

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

int main() {
    WSADATA wsaData;
    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {
        printf("Failed to initialize winsock.\n");
        return 1;
    }

    SOCKET sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock == INVALID_SOCKET) {
        printf("Failed to create socket.\n");
        WSACleanup();
        return 1;
    }

    // Perform ioctlsocket operation
    int result = ioctlsocket(sock, FIONBIO, 1);
    if (result == SOCKET_ERROR) {
        printf("ioctlsocket failed with error code: %d\n", WSAGetLastError());
    } else {
        printf("ioctlsocket succeeded.\n");
    }

    closesocket(sock);
    WSACleanup();
    return 0;
}