How does making the function static not solve this in C? Then the definition is local to the translation unit and there are no linkage concerns at all.
> Static but not inline functions will trigger warnings of unused functions.
Well, isn't it true? It's true also in the inline case. I consider it strange behavior not to emit an explicitly enabled warning for a case that definitely satisfies the warning conditions.
> Static and inline does not trigger this.
Tried -Wunused-function in gcc 6.3.0 and clang 3.8.1-24, with an unused-but-defined function declared "static inline int add(int a, int b)". clang still emits the warning, gcc does not.
If you're already dependent on whatever additional semantics gcc tacked onto the inline keyword you can as well use "__attribute__((unused))" to disable the warning for a particular function, which more clearly communicates the intent to disable the warning.
It turns out that the clang warnings work differently in header files, specifically. In my test I just put the static inline function in a C file. clang does however not trigger -Wunused-function when the static inline function is included from a header. The code is the same after pre-processor expansion.
IMO these special cases just add to the confusion and my criticism of strange behavior, but I stand corrected on the actual behavior of the two compilers.
