Re: Troubles with makefile

[Philip Guenther]

On Sun, Jun 8, 2008 at 8:26 AM, VitalyP <address@hidden> wrote:
> I am doing simple codegen with makefile. File gen.c is generated from
> gensrc.c. The example below works correctly and gen.c is generated
> when gensrc.c has more recent timestamp
...
> However in the example below gen.c is generated even if gensrc.c is
> older than gen.c. That is target 'prebuild' is always considered as
> not up-to date. Why is it so?
>
> .PHONY: prebuild
>
> test: gen.c
>    gcc -o $@ $<
>
> gen.c: prebuild
>
> prebuild: gensrc.c
>    # here goes some codegen command

As Sam says, because .PHONY targets are always out-of-date.  But what
are you trying to accomplish?  What is the 'prebuild' target supposed
to do?  My guess is that you want "make prebuild" to build the
generated source file(s).  To do that, you would make the generated
file(s) like gen.c prerequisites of prebuild, not the other way
around, ala:

prebuild: gen.c


Philip Guenther