7.4.3 Cache Checkpointing

If your configure script, or a macro called from ‘configure.ac’, happens to abort the configure process, it may be useful to checkpoint the cache a few times at key points using AC_CACHE_SAVE. Doing so reduces the amount of time it takes to rerun the configure script with (hopefully) the error that caused the previous abort corrected.

Macro: AC_CACHE_LOAD

Loads values from existing cache file, or creates a new cache file if a cache file is not found. Called automatically from AC_INIT.

Macro: AC_CACHE_SAVE

Flushes all cached values to the cache file. Called automatically from AC_OUTPUT, but it can be quite useful to call AC_CACHE_SAVE at key points in ‘configure.ac’.

For instance:

 … AC_INIT, etc. …

# Checks for programs.
AC_PROG_CC
AC_PROG_AWK
 … more program checks …
AC_CACHE_SAVE

# Checks for libraries.
AC_CHECK_LIB([nsl], [gethostbyname])
AC_CHECK_LIB([socket], [connect])
 … more lib checks …
AC_CACHE_SAVE

# Might abort…
AM_PATH_GTK([1.0.2], [], [AC_MSG_ERROR([GTK not in path])])
AM_PATH_GTKMM([0.9.5], [], [AC_MSG_ERROR([GTK not in path])])

 … AC_OUTPUT, etc. …

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