Problem between function pointers and [alleged] recursion.

[kender]

Colleagues,

Here’s an example, where compiler suspects that the there may be recursion and generates an error “Recursion not permitted (function_name)”. But, the recursion doesn’t actually happen.

Arguments in this example only make function signatures distinct. They don’t serve any other purpose.

[stinky]

Function pointers are not flawless in CCS. Recursion is not permitted and a call to a function pointer is actually calling a built in function. If you attempt to call it again you are inviting recursion.

[jeremiah]

To addon to what was said, the PIC micros don't natively support function pointers well. CCS has to do some tricky stuff to make it work on the architecture at all. One of those is an internal function it calls. If memory serves me correct, it is something like @gotoptr. Calling a recursive function within a recursive function calls @gotoptr inside @gotoptr, which is recursion.

So while it appears your methods don't recurse, they actually do in order to make function pointers work. It's a limitation of the hardware moreso than the compiler.

[FvM]

The problem behind "recursion not allowed" is that CCS C allocates storage for local variables and function
arguments globally, analyzing the call tree to avoid memory conflicts.

Function pointers break the compiler's ability to determine the call hierarchy. As you probably already know,
giving a different function type to the second level functions by adding a dummy argument is a workaround for the
present example.

[kender]