@node ax_subst_with
@unnumberedsec ax_subst_with

@majorheading Synopsis

@smallexample
AX_SUBST_WITH([varname])
@end smallexample

@majorheading Description

a very simple macro but also very helpful - the varname is usually the
one from an AC_ARG_ENABLE or AC_ARG_WITH option. it is transliterated
into uppercase and a prefix WITH_ and WITHOUT_ that are both _SUBSTed.

Only one of these is set to "#" while the other is empty. In other words
a call like AC_WITHNONE(enable-call) will create two SUBST-symbols as
WITH_ENABLE_CALL and WITHOUT_ENABLE_CALL. When the varname had been set
to something not "no" or "0" or ":" or "false" then it results in

@smallexample
 WITH_ENABLE_CALL="" ; WITHOUT_ENABLE_CALL="#"
@end smallexample

which you can use in your Makefile quite easily as if using an
AM_CONDITIONAL but which can be also parsed by normal make

USE = @@WITH_ENABLE_CALL@@ -Denabled USE = @@WITHOUT_ENABLE_CALL@@
-Dnot_enabled

@majorheading Source Code

Download the
@uref{http://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=blob_plain;f=m4/ax_subst_with.m4,latest
version of @file{ax_subst_with.m4}} or browse
@uref{http://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=history;f=m4/ax_subst_with.m4,the
macro's revision history}.

@majorheading License

@w{Copyright @copyright{} 2008 Guido U. Draheim @email{guidod@@gmx.de}}

Copying and distribution of this file, with or without modification, are
permitted in any medium without royalty provided the copyright notice
and this notice are preserved.  This file is offered as-is, without any
warranty.