On Fri, 2015-04-03 at 23:40 +0200, Petr Machata wrote:
Mark Wielaard <mjw(a)redhat.com> writes:
> Why is that mkdir now necessary?
It's not, but I thought it's a good idea for symmetry. The reason the
c++ bits need this mkdir is that we keep that code in a sub-directory,
and this creates the corresponding sub-directory for the dependency
tracking helper files.
Aha, ok thanks.
>> +AC_CACHE_CHECK([for working C++ compiler],
ac_cv_cxx_works,
>> +[AC_LANG_PUSH([C++])
>> + AC_COMPILE_IFELSE([AC_LANG_SOURCE([dnl
>> +struct foo {
>> + int i;
>> + explicit foo () : i (0) {}
>> + virtual ~foo () {}
>> +};])], ac_cv_cxx_works=yes, ac_cv_cxx_works=no)
>> + AC_LANG_POP()])
>> +AM_CONDITIONAL(HAVE_CXX, test "$ac_cv_cxx_works" = yes)
>
> We require gnu++98 above.
> Is the explicit enough to make sure the compiler supports C++98?
Well, this is a C++98 code. It's of course not enough to test the whole
C++98--the language is vast. The reason for that test is that I want to
make sure we really do have a C++ compiler. AC_PROG_CXX happily exports
CXX even if none is available, so we can't use that in conditionals.
I was mostly wondering whether we needed to add an command line argument
like -std=gnu++98 to be sure. But maybe that is all implicit and
standard for all gcc versions anyway.
Cheers,
Mark