Hey, On Wed, 16 Nov 2022, Alexander Monakov wrote: > > The idea is so obvious that I'm probably missing something, why autoconf > > can't use that idiom instead. But perhaps the (historic?) reasons why it > > couldn't be used are gone now? > > Ironically, modern GCC and LLVM optimize '&foobar != 0' to '1' even at -O0, > and thus no symbol reference remains in the resulting assembly. Err, right, *head-->table*. Playing with volatile should help: char foobar(void); char (* volatile ptr)(void); int main(void) { ptr = foobar; return ptr != 0; } Ciao, Michael.