How does a vendor supplied C++ library support multiple compilers?

Question

I make use of a vendor supplied library in a C++ program. All the vendor supplies is a .lib, .dll and the header files.

This library was first used in MSVC++ 6 and now in MSVC 2010.

It appears they support mingw, qt, etc. I have had no problems with using it in either debug or release mode.

I have recently added another dependency to the project, yaml-cpp, an open-source project that provides no binaries. I am able to build yaml-cpp using cmake and MSVC 2010 as a static library and can link it to my project successfully.

In order to do this I must link to the debug and release versions of the .lib respectively as I have run in to weird Microsoft CRT/linker issues I am just learning about.

I am curious, how does the vendor of my first library (libXl if you are curious) provide a .lib and .dll that works on a range of compilers without worrying about the CRT version?

How do you write code that allows this or is it the linking process? yaml-cpp is a cross platform library, is it possible for me to compile it in a similar way that would allow me to use a single .lib within my project?

I am not sure what resources to look for to learn more about it. How do people learn about this kind of stuff? Thanks!

Answer 1

The reason that a .lib and dll can work with a variety of compilers is down to ensuring that there are no compiler-specific dependencies in your code. .lib and .dll are not recompiled so once they are made they should be stand-alone if so coded, and their functionality can be accessed from anywhere with the ability to use a .dll or a .lib.

There is some discussion on the pros and cons of dll and lib here which you may find interesting.

Let me know if you need more info and I will do my best to oblige.