I was formerly involved in the development of the FreeBASIC compiler and runtime system. I no longer work on the FreeBASIC project, but a few documents are preserved here for historical curiosity.
To quote the official documentation:
"FreeBASIC - as the name suggests - is a completely free, open-source, 32-bit BASIC compiler, with the syntax the most compatible possible with MS-QuickBASIC, that adds new features such as pointers, unsigned data types, inline-assembly and many others."