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Re: The -e option confuses the $(origin ) ?
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From: |
Kaz Kylheku (gmake) |
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Subject: |
Re: The -e option confuses the $(origin ) ? |
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Date: |
Mon, 13 Sep 2021 07:32:20 -0700 |
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User-agent: |
Roundcube Webmail/0.9.2 |
On 2021-09-13 07:16, Kaz Kylheku (gmake) wrote:
It looks like -e is some sort of experimental hack with mysterious
effects that is under-documented on purpose, with a warning not to
use it.
Except, oops, POSIX specifies this option.
POSIX does not say that using -e is "not recommended" (or otherwise
deprecated or anything of the sort), and does not specify any weird
interaction with command line definitions or passage to sub-makes.
The only effect of -e should be that when a variable definition
occurring inside a makefile is being processed, then if the variable
exists in the environment, it overrides. That's it.
When we are testing a Makefile that contains no assignments to FOO,
then -e should make no difference to its behavior with regard to FOO,
because the only construct affected by -e is completely absent.
OTOH, POSIX also doesn't describe $(origin ...).
So that is to say, it's not clear whether a purely POSIX Makefile can
reproduce any -e nonconformance under GNU Make.
Since the GNU Manual does not recommend -e be used, it was likely given
low priority.