Comment by pizlonator

Fil-C is as compatible with C as different variants of C are with one another.

The porting effort is usually a less than if you were going from 32-bit to 64-bit for the first time. For some programs, you need zero changes.

In Qt I think the changes were stuff like:

- Use an intrinsic instead of inline assembly for cpuid.

- Change how a tagged pointer works (I.e. a 64-bit value used to store some integer bits and a pointer)

(Source: I’m the Fil-C guy and I watched the Qt porting happen from the sidelines.)