How do I make an AC_CACHE_CHECK critical?

Question

I perform some checks during configure, which i set up with autoconf using the AC_CACHE_CHECK macro. Some checks are critical, so if they donÄt pass, I want configure to fail. How can I achieve this?

Thanks, Steffen

Answer 1

Not sure what you mean. Do you want to abort if the result is not cached? Or, if the result is not cached, do you want to attempt to assign a value but abort if unsuccesful? For the latter, just do:

# Replace 3rd argument with commands to assign the cache variable
# See autoconf documentation for how to name the cache variable
AC_CACHE_CHECK([myvariable], [sss_cv_type_myvar], [sss_cv_type_myvar=yes])
myvariable=$sss_cv_type_myvar
AS_IF([test x"$myvariable" != xyes],[AC_MSG_ERROR(
    [myvariable not yes])])

If you want to abort merely because the variable is not cached, you could put an exit in the 3rd argument to AC_CACHE_CHECK. The commands in that option are used to assign the cache variable, and are not supposed to have side effects. Exiting the configure script is definitely a side effect, but that may be the behavior you want.