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Date: Fri, 24 Mar 2006 21:13:46 -0700
From: Eric Blake <ebb9 AT byu DOT net>
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Subject: Re: The binary "[.exe"
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According to Buchbinder, Barry (NIH/NIAID) [E] on 3/24/2006 7:59 PM:
> 
> "/bin/[ --help" gives a message while "/bin/test --help" is silent.
> (Interestingly, "strings /bin/test.exe" show that "test.exe" contains
> the help message.) "[ --version" give the FSF copyright notice while
> "strings test.exe" does not find one.

And I just traced down this difference.  By default, gcc/ld do not strip
out unused functions, if those functions appear in the same .o as
something else that is in use.  test.exe and [.exe are compiled from the
same test.c source file (with different #defines to choose which one is
being compiled, and therefore which functions are used), but the overall
executable links in other .o's.  The --help text is part of a method in
test.c, so it appears in both executables, even though it is in a dead
code path in test.exe; but the --version text is part of a method linked
in from a different source file version-etc-fsf.c (shared among all the
coreutils), and that .o was not needed to satisfy the linkage of test.exe.
 Hence test.exe is smaller in size, and has one but not both strings.

- --
Life is short - so eat dessert first!

Eric Blake             ebb9 AT byu DOT net
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