On Fri, 2010-07-02 at 17:08 +0800, Jiongliang Zhang wrote:
> ifndef MAKE_VERSION
> echo := $(shell echo "welcome...")
> endif
>
> if the echo := xxx is variable, but I can't get the value by this sentence:
> $(echo)
>
> so what's the first echo mean?
Are you sure that's the entire line, exactly as it appears? I doubt
that it is. Please don't ask what something means then paraphrase it:
that's not helpful.
>From your description I suspect that it's really something like this:
ifndef MAKE_VERSION
echo := $(shell echo "welcome..." 1>&2)
endif
In this syntax the shell command prints "welcome..." to the terminal
(via stderr). As a result the $(echo) variable is empty (because the
shell command invoked doesn't print anything to stdout).
--
-------------------------------------------------------------------------------
Paul D. Smith <psm...@gnu.org> Find some GNU make tips at:
http://www.gnu.org http://make.mad-scientist.net
"Please remain calm...I may be mad, but I am a professional." --Mad Scientist
