Howdy all! I'm working on netcdf, a popular freeware software library for climate scientists and meteorologists. I have an option in my configure.ac which allows the user to build an extra part of the package if they specify --enable-netcdf-4 during the configure step. If they do specify it, I need an automake variable (USE_NETCDF4) to be true, and I also need a macro (also USE_NETCDF4) defined in config.h. Here's how I do it, but I'm sure there must be a better way. In particular, how do I set the macro USE_NETCDF4 to 1, when AC_ARG_ENABLE sets ac_cv_use_netcdf4 to either "yes" or "no." The way I do it is to introduce a new variable, ac_use_netcdf4_num, which I set to 0 or 1. Is there a better way to do this? # Does the user want to build netcdf-4? AC_MSG_CHECKING([whether netCDF-4 is to be built]) AC_ARG_ENABLE([netcdf-4], [AS_HELP_STRING([--enable-netcdf-4], [build with netcdf-4 (HDF5 is required)])], [ac_cv_use_netcdf4=$enableval], [ac_cv_use_netcdf4=no]) AC_MSG_RESULT($ac_cv_use_netcdf4) AM_CONDITIONAL(USE_NETCDF4, [test x$ac_cv_use_netcdf4 != xno]) if test x$ac_cv_use_netcdf4 == xyes; then ac_use_netcdf4_num=1 else ac_use_netcdf4_num=0 fi AC_DEFINE_UNQUOTED([USE_NETCDF4], [$ac_use_netcdf4_num], [if true, build netCDF-4]) Thanks! Ed _______________________________________________ Autoconf mailing list Autoconf@xxxxxxx http://lists.gnu.org/mailman/listinfo/autoconf