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Re: Idea: Add .COMMANDCHANGE and .CACHE
From: |
David A. Wheeler |
Subject: |
Re: Idea: Add .COMMANDCHANGE and .CACHE |
Date: |
Mon, 10 Jun 2019 21:14:49 -0400 (EDT) |
On Mon, 10 Jun 2019 15:40:53 -0800, Britton Kerin <address@hidden> wrote:
> No, just the rules that :Makefile, which you can easily tune if it matters.
> Heck, you can include some_fragment.mk that has the recipes that
> are a concern and depend on that if you really need that granularity,
> and then the dependency that you want is explicit.
Using a lot of some_fragment.mk files gets you *closer*, but it's not
the same thing. My proposed .COMMANDCHANGE depends on
the *expanded* set of commands, not the original commands.
That way, if you change a value (say CCFLAGS) the set of commands
is considered *different* and will be re-run.
For example:
In file x.c.mk:
x.o: x.c
<TAB>$(CC) $(CCFLAGS) -o x.o x.c
In file Makefile:
include x.c.mk
main: x.o x.c.mk
...
Let's say I run this with:
make CCFLAGS="-O1" main
and in run #2 say:
make CCFLAGS="-O3" main
In run #2 the file x.c.mk has not changed,
and x.o is still after x.c.
Therefore, x.o will not be regenerated.
If we add:
.COMMANDCHANGE:
then a change to CCFLAGS *will* cause re-execution
of the rule that generates x.o.
--- David A. Wheeler
- Re: Idea: Add .COMMANDCHANGE and .CACHE, Britton Kerin, 2019/06/10
- Re: Idea: Add .COMMANDCHANGE and .CACHE,
David A. Wheeler <=
- Re: Idea: Add .COMMANDCHANGE and .CACHE, Britton Kerin, 2019/06/11
- Re: Idea: Add .COMMANDCHANGE and .CACHE, David A. Wheeler, 2019/06/11
- Re: Idea: Add .COMMANDCHANGE and .CACHE, Edward Welbourne, 2019/06/11
- Re: Idea: Add .COMMANDCHANGE and .CACHE, thutt, 2019/06/11
- Idea: Add command-line option for reporting potential makefile errors, David A. Wheeler, 2019/06/11
- Re: Idea: Add command-line option for reporting potential makefile errors, Tim Murphy, 2019/06/12
- Re: Idea: Add command-line option for reporting potential makefile errors, David A. Wheeler, 2019/06/12
- Re: Idea: Add command-line option for reporting potential makefile errors, David Boyce, 2019/06/12
- Re: Idea: Add command-line option for reporting potential makefile errors, Paul Smith, 2019/06/12
- Re: Idea: Add command-line option for reporting potential makefile errors, David A. Wheeler, 2019/06/12