On 10/26/2010 07:41 AM, David M. Warme wrote:
2. By creating both the dependency file and the actual m4 target
file in one step, you wind up being in danger of "circular
dependencies" -- running make twice in a row causes stuff to
be remade the second time. In certain cases, even an endless
succession of "make" invocations causes stuff to get remade
every time. Single commands that update two or more targets
at once are the usual cause of this behavior. The fix is to
have two separate rules in your Makefile:
I'm reluctant to have to require to run m4 twice per file. Dependencies
as a side effect of compilation is the most efficient way to generate
dependencies, and running twice defeats this. There's a reason that
automake prefers to generate dependencies during compilation, and if
automake can write portable makefiles with gcc dependencies generated
during compilation, then I see no reason why m4 can't be hooked up to do
the same.
--
Eric Blake [email protected] +1-801-349-2682
Libvirt virtualization library http://libvirt.org
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