Paul Eggert wrote: > > AC_CHECK_FUNC *should not* just probe for linkability of a symbol > > ... Autoconf cannot > be expected to know every signature of every function in every library. Clang will surely not acquire knowledge about "every library", right, only about the C library according to relevant standards (ISO C, POSIX)? > ... In the meantime if > Clang becomes pickier by default it would be helpful if there were a > well-defined way to shut off Clang's pickiness. To me it seems the problem is not Clang's pickiness, but rather the assumptions that it makes about the target environment. There is a documented way to ask Clang and GCC "assume a free-standing implementation, not an environment that has the ISO C / POSIX / LSB / ... functions": 1) -ffreestanding [1][2] 2) -fno-builtin Can we assume that these options will continue to work? If so, all Autoconf needs to do is to pass these options to the compiler in AC_CHECK_FUNC checks. Then we don't need to add knowledge about each of the hundreds of standard libc functions into Autoconf. Bruno [1] https://clang.llvm.org/docs/ClangCommandLineReference.html [2] https://gcc.gnu.org/onlinedocs/gcc-12.2.0/gcc/C-Dialect-Options.html
