I am building a C project for several compilers, some of which are legacy compilers which don't seem to have link time inlining support, so it seemed logical to place static inline functions directly in headers and actually have each translation unit have its own copy.
Also, I need to ensure certain functions are inlined so that there are no calls to other functions (i.e. changes to CPU registers) when called inside certain low-level interrupt handlers, so it's not simply about letting the compiler choose if it will affect performance.
However, a colleague of mine told me this is an unusual thing to do and I should avoid it. At this point in project I can probably still rearrange everything, so I would just like to confirm if there are some issues we might face in the long run if we decide to use header inlines?