dmitrii.pasechnik wrote: > By the way, ac_cv_sys_largefile_opts isn't fun to use - as sometimes > it's a plain text, and sometimes flags which should be added to CFLAGS. > So one has to write things like > > AS_CASE([$ac_cv_sys_largefile_opts], > ["none needed"], [], > ["support not detected"], [], > dnl otherwise it is a compiler flag > [LARGEFILECFLAGS="$ac_cv_sys_largefile_opts"] > ) > > which are unnecessarily complicated.
All ac_cv_* variables, and in fact all *_cv_* variables, are designed to contain the answer to a checking for <something>... output line, in a way that is both machine-parseable and human-readable. As a consequence: - Its values look sometimes odd (e.g. 'no (bad O_NOATIME, O_NOFOLLOW)'. - Its values are not stable over time and therefore *cannot be documented*. The entities which can often be documented are AC_SUBSTed variables and the C/C++ preprocessor macro definitions (AC_DEFINE). If there is the need for an Autoconf macro to expose more details, in a documented way, it should be done through a new AC_SUBSTed variable or a new AC_DEFINE. Bruno
