Re: [Savannah-users] what's this mean: echo := $(shell echo "welcome")

[Paul Smith]

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).

-- 
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