On Sunday, January 24, 2010, Ralf Wildenhues wrote: > * David Byron wrote on Fri, Jan 22, 2010 at 12:38:03AM CET: > > Let's say I have a header file named foo.h that contains: > > > > #define FOO an_interesting_value > > > > (I think) I'm looking for a macro like this: > > > > AC_GET_VALUE([foo.h],[FOO]) > > > > that populates ac_cv_value_of_FOO with an_interesting_value > > > > Does such a macro exist? Apologies if this is a FAQ. I > > can think of a way to do this by compiling a program > > that writes the result to a file, but that seems > > complicated and a struggle when cross-compiling. > > There is AC_COMPUTE_INT which allows you to compute the > integer (signed long) value of an arbitrary compile-time > expression. It is a bit overkill for your case (in a > cross-compile situation, it may need up to log_2(value) > compilations to find the value), but should work > nonetheless. I'm looking for a non-integer value in this case. > Autoconf provides AC_EGREP_CPP but that doesn't let you > get at the matched string. I think we should add > something like this, or allow AC_PREPROC_IFELSE to store > its output for inspection in the IF-TRUE branch. Making the output available on the IF-TRUE branch of AC_PREPROC_IFELSE is the thing that came to mind to me first. As I mentioned before I think I've convinced myself to go about what I'm doing a different way but I bet this would be useful to me sometime in the future or to other folks. Thanks much. -DB _______________________________________________ Autoconf mailing list Autoconf@xxxxxxx http://lists.gnu.org/mailman/listinfo/autoconf
