Copyright (C) 2000-2012 |
GNU Info (autoconf.info)Cache FilesCache Files ----------- A cache file is a shell script that caches the results of configure tests run on one system so they can be shared between configure scripts and configure runs. It is not useful on other systems. If its contents are invalid for some reason, the user may delete or edit it. By default, configure uses `./config.cache' as the cache file, creating it if it does not exist already. `configure' accepts the `--cache-file=FILE' option to use a different cache file; that is what `configure' does when it calls `configure' scripts in subdirectories, so they share the cache. Note: Subdirectories, for information on configuring subdirectories with the `AC_CONFIG_SUBDIRS' macro. Giving `--cache-file=/dev/null' disables caching, for debugging `configure'. `config.status' only pays attention to the cache file if it is given the `--recheck' option, which makes it rerun `configure'. If you are anticipating a long debugging period, you can also disable cache loading and saving for a `configure' script by redefining the cache macros at the start of `configure.in': define([AC_CACHE_LOAD], )dnl define([AC_CACHE_SAVE], )dnl AC_INIT(whatever) ... rest of configure.in ... It is wrong to try to distribute cache files for particular system types. There is too much room for error in doing that, and too much administrative overhead in maintaining them. For any features that can't be guessed automatically, use the standard method of the canonical system type and linking files (Note: Manual Configuration). The cache file on a particular system will gradually accumulate whenever someone runs a `configure' script; it will be initially nonexistent. Running `configure' merges the new cache results with the existing cache file. The site initialization script can specify a site-wide cache file to use instead of the default, to make it work transparently, as long as the same C compiler is used every time (Note: Site Defaults). If your configure script, or a macro called from configure.in, happens to abort the configure process, it may be useful to checkpoint the cache a few times at key points. Doing so will reduce the amount of time it takes to re-run the configure script with (hopefully) the error that caused the previous abort corrected. ... AC_INIT, etc. ... dnl checks for programs AC_PROG_CC AC_PROG_GCC_TRADITIONAL ... more program checks ... AC_CACHE_SAVE dnl checks for libraries AC_CHECK_LIB(nsl, gethostbyname) AC_CHECK_LIB(socket, connect) ... more lib checks ... AC_CACHE_SAVE dnl Might abort... AM_PATH_GTK(1.0.2, , exit 1) AM_PATH_GTKMM(0.9.5, , exit 1) automatically generated by info2www version 1.2.2.9 |