3.1.3 Standard configure.ac Layout

The order in which configure.ac calls the Autoconf macros is not important, with a few exceptions. Every configure.ac must contain a call to AC_INIT before the checks, and a call to AC_OUTPUT at the end (see Output). Additionally, some macros rely on other macros having been called first, because they check previously set values of some variables to decide what to do. These macros are noted in the individual descriptions (see Existing Tests), and they also warn you when configure is created if they are called out of order.

To encourage consistency, here is a suggested order for calling the Autoconf macros. Generally speaking, the things near the end of this list are those that could depend on things earlier in it. For example, library functions could be affected by types and libraries.

     Autoconf requirements
     AC_INIT(package, version, bug-report-address)
     information on the package
     checks for programs
     checks for libraries
     checks for header files
     checks for types
     checks for structures
     checks for compiler characteristics
     checks for library functions
     checks for system services
     AC_CONFIG_FILES([file...])
     AC_OUTPUT