Hi, In recent versions of Autoconf, AC_TYPE_LONG_LONG_INT (and AC_TYPE_UNSIGNED_LONG_LONG_INT) wrongly indicate that (unsigned) long long is supported on compilers which actually do not support it.
Looking at the implementation of AC_TYPE_LONG_LONG_INT, it contains: ac_cv_type_long_long_int=yes case $ac_prog_cc_stdc in no | c89) ;; *) [ run compiler probes ] esac which looks like it is assuming "long long" is supported for pre-standard and C89 compilers, only actually running checks on compilers which support newer C standards; presumably this is the opposite of what is intended. The failure is easy to demonstrate with gcc: % cat >configure.ac <<'EOF AC_INIT([test], [0]) AC_PROG_CC AC_TYPE_LONG_LONG_INT AC_OUTPUT EOF % autoconf-2.72 --force % ./configure CC='gcc -Werror=long-long' [...] checking for gcc -Werror=long-long option to enable C11 features... unsupported checking for gcc -Werror=long-long option to enable C99 features... unsupported checking for gcc -Werror=long-long option to enable C89 features... none needed checking for unsigned long long int... yes checking for long long int... yes The last apparently working version is autoconf-2.70, but that is because this version of autoconf has a different bug which causes it to believe C89 compilers support C99 (so the long long test is run in this version). The last actually working version is autoconf-2.69: % autoconf-2.69 --force % ./configure CC='gcc -Werror=long-long' [...] checking for gcc -Werror=long-long option to accept ISO C89... none needed checking for unsigned long long int... no checking for long long int... no Cheers, Nick
