unresolved external symbol in6addr_loopback

Question

Get:

unresolved external symbol in6addr_loopback

Because of this:

In ws2ipdef.h

Begin with:

#ifdef __cplusplus
extern "C" {
#endif

extern CONST IN6_ADDR in6addr_loopback;

In in6addr.h

typedef struct in6_addr {
    union {
        UCHAR       Byte[16];
        USHORT      Word[8];
    } u;
} IN6_ADDR, *PIN6_ADDR, FAR *LPIN6_ADDR;

Thats all. Why can't it find in6addr_loopback

It is not my code. It is from:

https://mosquitto.org/

Answer 1

I just downloaded Mosquitto and I could compile the \lib ([File] [New] [Project From Existing Code...]) with :

[C++] [Preprocessor] Preprocessor Definitions

WIN32;mosquittopp_EXPORTS

[Linker] [Input] Additional Dependencies

Ws2_32.lib

[General] [Configuration Type]

Dynamic Library (.dll)

=>

1>Mosquito.vcxproj -> E:\Sources\mosquitto-master\lib\x64\Debug\Mosquito.dll

1>Done building project "Mosquito.vcxproj".

========== Build: 1 succeeded, 0 failed, 0 up-to-date, 0 skipped ==========

Answer 2

I didn't do a DLL file but change C++ and Linker as you have done and now I can start the app but it crasches all the time because they use lot of pionters with no values in the mosquitto code and you get access violation. I have all the code in one file just to debug it.

I'm using Visual Studio 2022 and you can't do x86 C++ program anymore. You get error in .h files if you try.

So thanks for the tips about ws2_32.lib. I checked the linker att that lib was missing.