Are C and C++ .lib files portable?

Question

Assuming the code compiled is actually portable (just using standard library stuff or whatever), could I use the same .lib for my projects across multiple platforms, or can they only run on the platform they were compiled on?

I'm porting my C++ project from Windows to Linux and I use a few 3rd party libraries including openAL, FreeType and FreeImage, and I would like to know if I have to get/recompile new library files.

Answer 1

The dynamic linkers on Windows and Linux work in completely different ways. On Linux the linker will expect elf format .so files. Windows however uses .lib and .dll files which are in a different, incompatible format.

Even if you were to find a way around this, the default calling conventions between the two OSes are different. C function calls place the arguments into different registers so it would be impossible to call functions in these lib files without having the compiler use a custom calling convention, however this would prevent any other code from calling your libraries.

The Wine Project has created a compatibility layer to allow Windows binaries to call into libraries compiled for Linux, however there is a significant performance and complexity penalty to such a layer.

In short, you would be best off in nearly every case to recompile the project for both OSes separately. The libraries you mention (afaik) are all available for Linux also so porting should be a breeze.

Answer 2

The entire purpose of languages like C++ is to provide a platform-agnostic source code abstraction that is portable, because the code created by compiling your C++ is not.

You shall have to rebuild it for your target platform.

Answer 3

.lib files contain platform-specific object code. You will need different ones for each platform.

You will have to recompile the other libraries on each platform you port to.