我刚刚通过“Beej的网络编程指南”一书开始学习winsock。我正在windows下编程并通过gcc运行它。这只是编写我的第一个服务器程序的开始，但是当我尝试编译时它给了我这些错误。
/* Server */
#include <iostream>
#include <windows.h>
#include <winsock2.h>
using namespace std;
const int winsockVersion = 2;
#define BACKLOG 10
#define PORT 3000
int main(void){
WSADATA wsadata;
if (WSAStartup(MAKEWORD(winsockVersion,0),&wsadata) == 0){
struct addrinfo hints, *res;
memset(&hints,0,sizeof hints);
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = AI_PASSIVE;
if ( getaddrinfo(NULL,PORT,&hints,&res) == 0 ){
cout<<"-Call to get addrinfo successful!." << endl;
}
cout<<"res af_family" << res->ai_family << endl;
}
//clear stuff
if( WSACleanup() != 0){
cout<<"-WSACleanup unsuccessful" << endl;
}else{
cout<<"-WSACleanup successful" << endl;
}
return 0;
}
这些是我收到的错误
g++ -o server.exe server.cpp -lws2_32
Process started >>>
server.cpp: In function `int main()':
server.cpp:20: error: aggregate `addrinfo hints' has incomplete type and cannot be defined
server.cpp:25: error: `AI_PASSIVE' was not declared in this scope
server.cpp:27: error: `getaddrinfo' was not declared in this scope
server.cpp:31: error: invalid use of undefined type `struct addrinfo'
server.cpp:20: error: forward declaration of `struct addrinfo'
server.cpp:54:2: warning: no newline at end of file
<<< Process finished.
不应该在windows.h或winsock.h中定义结构和函数吗？
解
对任何偶然发现此事的人进行编辑，添加
#define _WIN32_WINNT 0x501
#include <ws2tcpip.h>
如果getaddrinfo说它未声明，则在你的源代码顶部。
你可能想要#include <ws2tcpip.h>。请记住，在Stack Overflow之前，Google是您这类问题的朋友：您将从MSDN获得即时答案！
MSDN说我们应该#include <ws2tcpip.h>，但在ws2tcpip.h我找到了这段代码：
#if (_WIN32_WINNT >= _WIN32_WINNT_WINXP)
/**
* For WIN2K the user includes wspiapi.h for these functions.
*/
void WSAAPI freeaddrinfo (struct addrinfo*);
int WSAAPI getaddrinfo (const char*,const char*,const struct addrinfo*,
struct addrinfo**);
int WSAAPI getnameinfo(const struct sockaddr*,socklen_t,char*,DWORD,
char*,DWORD,int);
#endif /* (_WIN32_WINNT >= _WIN32_WINNT_WINXP) */
这意味着，_WIN32_WINNT的定义低于_WIN32_WINNT_WINXP，但当我尝试包括wspiapi.h时，我得到了"no such file or directory"。我的猜测是，这是MinGW的错，其中库的不同部分具有不一致的版本。在包括#define _WIN32_WINNT _WIN32_WINNT_WINXP之前，你必须自己ws2tcpip.h
谨防！你的包含是错误的。问题是windows.h已经包含winsock.h和winsock2.h然后重新定义了一些结构和函数，导致大量的编译错误。移动windows.h包括在winsock2.h包括下面，或者只是删除windows.h包括，winsock2.h包括windows.h。
我能够使用以下包含，pragma和定义......
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdio.h>
#pragma comment(lib, "ws2_32.lib")
此答案的必要包含列表显示在Microsoft文章中：Winsock Includes
这对我有用：
#include <winsock2.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#define DEFAULT_PORT 80
void error_die(const char *s)
{
fprintf(stderr, "Error: %s failed with error %d\n", s, WSAGetLastError());
WSACleanup();
exit(EXIT_FAILURE);
}
int main(int argc, char **argv)
{
char response[] = "HTTP/1.1 200 OK\r\n"
"Content-Type: text/html; charset=UTF-8\r\n\r\n"
"<!DOCTYPE html><html><head><title>Hello World</title></head>"
"<body><h1>Hello world!</h1></body></html>\r\n";
char buf[4096];
int msg_len, addr_len;
struct sockaddr_in local, client_addr;
SOCKET sock, msg_sock;
WSADATA wsaData;
if (WSAStartup(MAKEWORD(2, 2), &wsaData) == SOCKET_ERROR)
{
fprintf(stderr, "WSAStartup failed with error %d\n", WSAGetLastError());
WSACleanup();
return -1;
}
// Fill in the address structure
local.sin_family = AF_INET;
local.sin_addr.s_addr = INADDR_ANY;
local.sin_port = htons(DEFAULT_PORT);
sock = socket(AF_INET, SOCK_STREAM, 0); //TCP socket
if (sock == INVALID_SOCKET)
error_die("socket()");
if (bind(sock, (struct sockaddr *)&local, sizeof(local)) == SOCKET_ERROR)
error_die("bind()");
if (listen(sock, 5) == SOCKET_ERROR) // wait for connection
error_die("listen()");
printf("Waiting for connection...\n");
while (1)
{
addr_len = sizeof(client_addr);
msg_sock = accept(sock, (struct sockaddr*)&client_addr, &addr_len);
if (msg_sock == INVALID_SOCKET || msg_sock == -1)
error_die("accept()");
printf("Accepted connection from %s, port %d\n", inet_ntoa(client_addr.sin_addr), htons(client_addr.sin_port));
msg_len = recv(msg_sock, buf, sizeof(buf), 0);
printf("Bytes Received: %d, message: %s from %s\n", msg_len, buf, inet_ntoa(client_addr.sin_addr));
msg_len = send(msg_sock, response, sizeof(response)-1 , 0);
if (msg_len == SOCKET_ERROR)
error_die("send()");
if (!msg_len)
{
printf("Client closed connection\n");
closesocket(msg_sock);
WSACleanup();
return -1;
}
closesocket(msg_sock);
}
WSACleanup();
}