Build failure with GCC 15 (incompatible pointer types) #5857
Description
Original report: https://bugs.gentoo.org/944036
GCC 15 has -Werror=incompatible-pointer-types and std=gnu23 by default, and this is causing some issues with the function pointers that GAP passes around. For example,
src/bool.c: In function 'InitKernel':
src/bool.c:332:22: error: passing argument 1 of 'InitHandlerFunc' from incompatible pointer type [-Wincompatible-pointer-types]
332 | InitHandlerFunc( ReturnTrue1, "src/bool.c:ReturnTrue1" );
| ^~~~~~~~~~~
| |
| struct OpaqueBag * (*)(struct OpaqueBag *, struct OpaqueBag *)
In file included from src/bool.c:20:
src/calls.h:416:30: note: expected 'ObjFunc' {aka 'struct OpaqueBag * (*)(void)'} but argument is of type 'struct OpaqueBag * (*)(struct OpaqueBag *, struct OpaqueBag *)'
416 | void InitHandlerFunc(ObjFunc hdlr, const Char * cookie);
(and many others like it).
After investigating the same issue in cvec, it looks like the issue can be traced back to the ObjFunc typedef. In C23, foo() means that foo takes zero arguments, so a cast is needed if you want to pass in a function that takes arguments in place of such a foo().