5.10.3 C++ Compiler Characteristics

Macro: AC_PROG_CXX ([compiler-search-list])

Determine a C++ compiler to use. Check if the environment variable CXX or CCC (in that order) is set; if so, then set output variable CXX to its value.

Otherwise, if the macro is invoked without an argument, then search for a C++ compiler under the likely names (first g++ and c++ then other names). If none of those checks succeed, then as a last resort set CXX to g++.

This macro may, however, be invoked with an optional first argument which, if specified, must be a space separated list of C++ compilers to search for. This just gives the user an opportunity to specify an alternative search list for the C++ compiler. For example, if you didn't like the default order, then you could invoke AC_PROG_CXX like this:

AC_PROG_CXX(cl KCC CC cxx cc++ xlC aCC c++ g++ egcs gcc)

If using the GNU C++ compiler, set shell variable GXX to `yes'. If output variable CXXFLAGS was not already set, set it to `-g -O2' for the GNU C++ compiler (`-O2' on systems where G++ does not accept `-g'), or `-g' for other compilers.

Macro: AC_PROG_CXXCPP

Set output variable CXXCPP to a command that runs the C++ preprocessor. If `$CXX -E' doesn't work, `/lib/cpp' is used. It is only portable to run CXXCPP on files with a `.c', `.C', or `.cc' extension.

If the current language is C++ (see section 6.7 Language Choice), many of the specific test macros use the value of CXXCPP indirectly by calling AC_TRY_CPP, AC_CHECK_HEADER, AC_EGREP_HEADER, or AC_EGREP_CPP.

Some preprocessors don't indicate missing include files by the error status. For such preprocessors an internal variable is set that causes other macros to check the standard error from the preprocessor and consider the test failed if any warnings have been reported. However, it is not known whether such broken preprocessors exist for C++.