(automake.info)Invoking aclocal

5.3 Auto-generating aclocal.m4
==============================

Automake includes a number of Autoconf macros which can be used in your
package (Note: Macros); some of them are actually required by
Automake in certain situations.  These macros must be defined in your
`aclocal.m4'; otherwise they will not be seen by `autoconf'.

   The `aclocal' program will automatically generate `aclocal.m4' files
based on the contents of `configure.ac'.  This provides a convenient
way to get Automake-provided macros, without having to search around.
The `aclocal' mechanism allows other packages to supply their own
macros (Note: Extending aclocal).  You can also use it to maintain
your own set of custom macros (Note: Local Macros).

   At startup, `aclocal' scans all the `.m4' files it can find, looking
for macro definitions (Note: Macro search path).  Then it scans
`configure.ac'.  Any mention of one of the macros found in the first
step causes that macro, and any macros it in turn requires, to be put
into `aclocal.m4'.

   _Putting_ the file that contains the macro definition into
`aclocal.m4' is usually done by copying the entire text of this file,
including unused macro definitions as well as both `#' and `dnl'
comments.  If you want to make a comment which will be completely
ignored by `aclocal', use `##' as the comment leader.

   When a file selected by `aclocal' is located in a subdirectory
specified as a relative search path with `aclocal''s `-I' argument,
`aclocal' assumes the file belongs to the package and uses `m4_include'
instead of copying it into `aclocal.m4'.  This makes the package
smaller, eases dependency tracking, and cause the file to be
distributed automatically.  (Note: Local Macros, for an example.)
Any macro which is found in a system-wide directory, or via an absolute
search path will be copied.  So use `-I `pwd`/reldir' instead of `-I
reldir' whenever some relative directory need to be considered outside
the package.

   The contents of `acinclude.m4', if this file exists, are also
automatically included in `aclocal.m4'.  We recommend against using
`acinclude.m4' in new packages (Note: Local Macros).

   While computing `aclocal.m4', `aclocal' runs `autom4te' (Note: Using
`Autom4te'.) in order to trace the macros
which are really used, and omit from `aclocal.m4' all macros which are
mentioned but otherwise unexpanded (this can happen when a macro is
called conditionally).  `autom4te' is expected to be in the `PATH',
just as `autoconf'.  Its location can be overridden using the
`AUTOM4TE' environment variable.

aclocal options

Options supported by aclocal

Macro search path

How aclocal finds .m4 files