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From:	Ken Brown <kbrown AT cornell DOT edu>
To:	cygwin <cygwin AT cygwin DOT com>
Subject:	Deterministic builds
Message-ID:	<ff5f5b20-33e2-ef2d-012a-a9e02903ba21@cornell.edu>
Date:	Wed, 4 May 2016 09:38:39 -0400
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Is it possible to build an executable on Cygwin so that subsequent 
builds (with no change in source) produce identical results?  Currently, 
the timestamp embedded in executables prevents this.  (I don't know if 
that's the only obstacle.)

For example:

$ cat hello.c
#include <stdio.h>
int
main ()
{
  printf("Hello, world!\n");
  return 0;
}

$ gcc hello.c -o hello1

$ gcc hello.c -o hello2

$ objdump -p hello1.exe | grep Time/Date
Time/Date               Wed May  4 09:20:24 2016

$ objdump -p hello2.exe | grep Time/Date
Time/Date               Wed May  4 09:20:29 2016

My actual use case is that I'm building a package that produces a large 
number of executables.  If I make a change in one source file, I'd like 
to be able to know which executables change.

Ken


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