Re: Is it safe to use ax_gcc_builtin to detect __builtin_offsetof?

On Sun, Feb 25, 2024 at 2:09 AM Jeffrey Walton <[email protected]> wrote:
>
> The page <https://www.gnu.org/software/autoconf-archive/ax_gcc_builtin.html>
> does not list __builtin_offsetof in the list of documented builtins.
> But the page says "Unsupported built-ins will be tested with an empty
> parameter set and the result of the check might be wrong or
> meaningless so use with care."
>
> Is it safe to use ax_gcc_builtin to detect __builtin_offsetof?
>
> Sorry to ask. Google is not returning useful results.

Cancel. We can't use AX_GCC_BUILTIN in production. Using
AX_GCC_BUILTIN produces broken configure's:

checking for getpagesize... yes
checking for working mmap... yes
checking for gettimeofday... yes
./configure: line 15023: syntax error near unexpected token `__builtin_offsetof'
./configure: line 15023: `AX_GCC_BUILTIN(__builtin_offsetof)'

Jeff