Hello, On 2014-11-28 11:51 +0100, Shahbaz Youssefi wrote: > The problem is that if you call AC_PROG_CXX, even if there are no C++ > compilers, *CXX is set to g++ anyway* and the macro doesn't provide a means > to understand if it actually succeeded or not. This is a problem because if > you want to enable a feature only if a C++ compiler exists, you need to be > able to well, check if there is a C++ compiler. This is the relevant Stack > Overflow question: http://stackoverflow.com/q/27111000/912144 > > Now I'm by no means an expert with m4, but I think I could hack away at > this. Before sending a patch however, I wanted to make sure if the idea is > acceptable. To contrast: AC_PROG_CC behaviour is to fail hard if no C compiler is found (or if certain tests of it fail). You may find that defining what "succeeded" means for AC_PROG_CXX will be hard to do. But you can always do something like this in configure.ac (totally untested): AC_PROG_CXX AC_LANG([C++]) AC_CACHE_CHECK([whether the C++ compiler works], [my_cv_cxx_works], [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([#include <iostream>], [std::cout << "Hello, World" << std::endl;])], [my_cv_cxx_works=yes], [my_cv_cxx_works=no])]) AS_IF([test x"$my_cv_cxx_works" != x"yes"], [AC_MSG_ERROR([sorry, can't help you])]) Perhaps AC_PROG_CXX would be improved by simply performing a test like the above at the end. Regards, -- Nick Bowler, Elliptic Technologies (http://www.elliptictech.com/) _______________________________________________ Autoconf mailing list Autoconf@xxxxxxx https://lists.gnu.org/mailman/listinfo/autoconf
