Implicit declaration of function 'getaddrinfo' on MinGW

Question

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

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

When I comp

Answer 1

Supposedly the proper way to fix this is:

#define WINVER WindowsXP

Or perhaps more sensibly adding -DWINVER=WindowsXP to your CPPFLAGS.

Ref: http://mingw.5.n7.nabble.com/Undefined-reference-to-getaddrinfo-td5694.html

Note: didn’t work for me however.

Answer 2

If you want to make your code compiler-wide you should actually also define NTDDI_VERSION with the same OS version as _WIN32_WINNT. Without that defining only _WIN32_WINNT will not let you to use getaddrinfo() with some compilers (i.e. Watcom). It is better to wrap it in the same way as Windows SDK does:

#define _NTDDI_VERSION_FROM_WIN32_WINNT2(ver)    ver##0000
#define _NTDDI_VERSION_FROM_WIN32_WINNT(ver)     _NTDDI_VERSION_FROM_WIN32_WINNT2(ver)

#ifndef _WIN32_WINNT
#  define _WIN32_WINNT 0x501
#endif
#ifndef NTDDI_VERSION
#  define NTDDI_VERSION _NTDDI_VERSION_FROM_WIN32_WINNT(_WIN32_WINNT)
#endif

Answer 3

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

Just #define _WIN32_WINNT before your includes.