看看下面这个小程序的问题。
#define WIN32_LEAN_AND_MEAN
#include <stdio.h>
#include <windows.h>
#include <winsock.h>
#pragma comment(lib, "ws2_32.lib")
int main()
{
WSADATA wsaData;
::WSAStartup(0x0202, &wsaData);
SOCKET s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
int t, n;
n = getsockopt(s, SOL_SOCKET, SO_RCVBUF, (char*)&t, &n); // 为什么会调用失败呢?
::WSACleanup();
return 0;
}