Question

I’m building a socket program in Visual Studio 2003 .NET

I #include <winsock2.h> header file but also noticed that I had to link in the WS2_32.lib to fix the unresolved winsock function errors.

In other homework projects, I just added a header file and used it’s functions – without adding the corresponding library.

How is this so?

Are some standard header file libraries already pre-linked in Visual Studio or something else?

Thank You!

Answer 1

The socket functions are actually implemented in ws2_32.dll. In order for the linker to be able to find them, you need to add the ws2_32.lib import library to your project. Note that the import library does not contain the actual code for the functions, but only information about where to find the actual functions (in ws2_32.dll).

You don’t mention which other header files you’re referring to, but if it’s something like <string.h> then that is already in the MSVC runtime library; if it’s something like <windows.h> then those functions are provided by import libraries such as kernel32.lib, user32.lib, and gdi32.lib. Those libraries are probably already included in your linker settings.