Date: Wed, 28 Jun 1995 09:44:56 -0400
From: kagel AT quasar DOT bloomberg DOT com
To: A DOT APPLEYARD AT fs2 DOT mt DOT umist DOT ac DOT uk
Cc: DJGPP AT sun DOT soe DOT clarkson DOT edu
Subject: Re: Size of a.out
Reply-To: kagel AT ts1 DOT bloomberg DOT com


   C++ program             A.OUT size unstripped    A.OUT size stripped
   int x[10000]; main(){}  52269                    44140
   main(){}                15387                     7276
      (difference)         36882                    36864

     Why does declaring the array `x' add so much size to A.OUT? Surely there
   is a more compact way of telling the loader to set the next 40000 bytes of
   RAM to all zeros, than to write out 40000 zeros at length in the .EXE file?
   Long ago in the CDC7600 mainframe's equivalent of .EXE files, there was a
   special compact notation for "repeat the next n bytes p times". Why not in
   PC's? (I know that the A.OUT from `int x[10000]; main(){}' contains 40000
   consecutive ascii-zeros that aren't in the A.OUT from `main(){}': I just
   looked!)

I agree.  The global declaration, 'int x[10000]', is "uninitialized data".
This should be noted in the symbol table and the startup code should allocate
the space for all uninitialized data in a contiguous, virtual, block and null
it out.  

Only initialized data should be written to the a.out (ie. int y[5] = {1, 2, 3,
4, 5};)  

-- 
Art S. Kagel, kagel AT ts1 DOT bloomberg DOT com

Variety is the soul of pleasure.  --  Aphra Behn