As far as I can tell, Autoconf provides no documented macro that allows me to run the preprocessor and capture (selected portions of) its output in shell variables. What is the most reliable way to do this with released versions of Autoconf? (Ideally something that would work over the entire 2.5x series.) A concrete example of what I am trying to do: The program whose configure script I am hacking embeds a copy of a library, libpcre. That library exposes its version number as a pair of #defines in its primary header file, pcre.h. It would be nice to allow the program to be linked against a system-provided copy of libpcre when possible; however, each version of the program needs to be linked with one and only one version of libpcre, because successive releases of libpcre add features which translate directly into user-visible features of the program. (It is a regular expression library.) So what I want to do is compare the system's pcre.h's definition of the version number macros with the bundled copy's. I had thought to do something like this: AC_PREPROC_IFELSE( [@%:@include <pcre.h> xxpcre_major="PCRE_MAJOR" xxpcre_minor="PCRE_MINOR"], [eval `egrep '^xxpcre_(major|minor)=' conftest.out` ac_cv_lib_pcre_version="$xxpcre_major.$xxpcre_minor"] [ac_cv_lib_pcre_version=unknown]) repeat for the bundled "pcre/pcre.h" with a different result variable, and then compare them. But AC_PREPROC_IFELSE sends the preprocessor output to /dev/null rather than conftest.out. :-( TIA zw _______________________________________________ Autoconf mailing list Autoconf@xxxxxxx http://lists.gnu.org/mailman/listinfo/autoconf
