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Re: [Axiom-developer] ENV

From: root
Subject: Re: [Axiom-developer] ENV
Date: Wed, 22 Nov 2006 17:04:01 -0500

> It may help to state the *specific meaning* of ENV in POSIX shells. I 
> looked at the man page for bash and it says:
>   "When invoked as an interactive shell with the name sh, bash looks for 
> the variable ENV, expands its value  if  it  is defined,  and uses the 
> expanded value as the name of a file to read and execute."
> So I can imagine a call to "$ENV sh something" in a makefile to explode. 
> What actually happened?

The shell never sees "$ENV". That's part of the confusion.
The ${ENV} variable is a makefile-level variable which is
expanded by make to read:

SPAD=.... SRC=... INT=... .... make src

The fact that the characters ENV is used as the name of the makefile
variable is a product of history. It would be trivial to rename the
variable from ENV to TPD and everything still works. 

Every programmer knows that the name of a variable in a local
context can be overloaded. I can't imagine why this is even a
point of discussion. There should be NO confusion between a
variable in a makefile and a variable in a shell.


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