MinGW上函数'getaddrinfo'的隐式声明 [英] Implicit declaration of function 'getaddrinfo' on MinGW

问题描述

我有一个使用getaddrinfo()的C程序.它可以在Linux和Mac OS X上正常运行.

I have a C program that uses getaddrinfo(). It works as expected on Linux and Mac OS X.

我正在将其移植到Windows.

I'm in the middle of porting it to Windows.

当我使用MinGW gcc编译它时，收到以下警告:

When I compile it (with MinGW gcc) I get the following warnings:

ext/socket/socket.c: In function 'sl_tcp_socket_init':
ext/socket/socket.c:98:5: warning implicit declaration of function 'getaddrinfo' [-Wimplicit-function-declaration]
ext/socket/socket.c:104:9: warning implicit declaration of function 'freeaddrinfo' [-Wimplicit-function-declaration]

然后整个事情都无法链接到未定义的对getaddrinfo()和freeaddrinfo()的引用.

Then the entire thing fails to link with undefined references to getaddrinfo() and freeaddrinfo().

现在，根据此MSDN页面，Windows上支持getaddrinfo()，它位于头文件Ws2tcpip.h和库文件Ws2_32.lib中.

Now, according to this MSDN page, getaddrinfo() is supported on Windows and is located in the header file Ws2tcpip.h and the library file Ws2_32.lib.

我包括了Ws2tcpip.h并与-lWs2_32链接，所以我不确定为什么它不起作用.

I'm including Ws2tcpip.h and linking with -lWs2_32, so I'm not sure why this isn't working.

推荐答案

如果看一下ws2tcpip.h的第297行，您会看到对_WIN32_WINNT的值进行了检查.

If you have a look at line 297 of ws2tcpip.h, you can see that there's a check of the value of _WIN32_WINNT.

#if (_WIN32_WINNT >= 0x0501)
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);
#else
/* FIXME: Need WS protocol-independent API helpers.  */
#endif

只需在包含之前#define _WIN32_WINNT.

Just #define _WIN32_WINNT before your includes.

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