> 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, or override documented cache variables on the configure command line.
> By default, configure uses no cache file, to avoid problems caused by accidental use of stale cache files.
> To enable caching, configure accepts --config-cache (or -C) to cache results in the file config.cache. Alternatively, --cache-file=file specifies that file be the cache file. The cache file is created if it does not exist already. When configure calls configure scripts in subdirectories, it uses the --cache-file argument so that they share the same cache. See Configuring Other Packages in Subdirectories, for information on configuring subdirectories with the AC_CONFIG_SUBDIRS macro.
But it doesn’t work reliably. If you change the configuration options, you have to clear the cache. The cache contents are not reliably shareable between multiple projects or different versions of autotools.
In case folks don't know, caching exists:
> 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, or override documented cache variables on the configure command line.
> By default, configure uses no cache file, to avoid problems caused by accidental use of stale cache files.
> To enable caching, configure accepts --config-cache (or -C) to cache results in the file config.cache. Alternatively, --cache-file=file specifies that file be the cache file. The cache file is created if it does not exist already. When configure calls configure scripts in subdirectories, it uses the --cache-file argument so that they share the same cache. See Configuring Other Packages in Subdirectories, for information on configuring subdirectories with the AC_CONFIG_SUBDIRS macro.
* https://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/a...