The Allegro game development library was originally developed for DJGPP in DOS, but there are now ports to several Windows compilers using DirectX, as well as a Linux port and a MacOS port.

It is designed for source code to be 100% portable between different platforms. That has some negative effects, especially in the Windows ports where it makes it difficult if not impossible to use the lower-level DirectX functions.

Apart from that (and it's inability to match the efficiency of a lower-level library like DirectX or SDL), it is an excellent library with a huge amount of functions that greatly simplify the process of creating a game.