Re: Canned command sequences

[Ted Stern]

On 20 Jun 2003, Sam Ravnborg wrote:
> Hi all.
>
> Posted the following a few weeks ago - wondered if anyone could explain it.
> I have stripped down the background info a bit - so the essense is kept.
>
        <snip>

>> 
>> The culprint is the extra line:
>> "echo hello again"
>> It should not be there.

Speaking only as another user ...

The essence of what you are asking is, "Why isn't the '@' indication of
no-echo respected by Make's $(call ) function and applied to the entire call?

IIUC, the answer is that you need to consider how "define/endef" differs from
a simple variable definition.

define/endef treats line endings differently -- it was specifically designed
so that you could create a function with each line written as it would be in a
target rule.  When a define-function is called, those line endings mean that
each line of $(rule_up) starts a new shell process.

In other words, what the "all" target sees after $(call) is evaluated is
something like

       all:
       <TAB> @set -e; <TAB> echo hello
       <TAB> echo hello again

Both '@' and the shell setting 'set -e' are applied only to the first shell,
so the second line of $(rule_up) is echoed.

Paul, did I get that right?

Ted
-- 
 Ted Stern                                 Applications Group
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