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From: S170MIKO@HTIKHT5.BITNET
Newsgroups: mod.computers.vax
Subject: Re: VAX C bug
Message-ID: <8611011438.AA23299@ucbvax.berkeley.edu>
Date: Fri, 31-Oct-86 12:29:00 EST
Article-I.D.: ucbvax.8611011438.AA23299
Posted: Fri Oct 31 12:29:00 1986
Date-Received: Mon, 3-Nov-86 20:56:31 EST
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Gary McDonald writes:
   >  The following program WON'T compile as is:
   >
   >  ==================
   >  /* from page 1-20 PROGRAMMING IN VAX C */
   >  #include stdio
   >  int *pointer;
   >  int x=10, y=0;
   >  main()
   >  {
   >    pointer=&x;
   >    y=*pointer;
   >    printf("values are %d %d %d\n",pointer,x,y);
   >  }
   >  ===================
   >  but will with these changes:
   >  ===================
   >    pointer= &x;
   >    y= *pointer;
   >  ===================
   >
   >  Is this a *known* bug??

Well, you're wrong both ways: this is *not exactly* the way the example
in the manual is written, and it is not a bug but a *feature*.
The problem is that this is one of the few cases where spacing is
significant, and it is meant to be.
This is because  =&  and  =*  are actually alternative ways to write the
operators  &=  and  *= , and with a space in between they mean just what you
think they mean. This is mentioned (briefly) in the manual on pages 4-19 &
4-20.
The examples in the manual always include lots of (insignificant) spaces
just to improve readability, so it's not obvious that these two spaces
immediately after  =  are really necessary to avoid ambiguity, but they are
there in the example.

By the way, if you're working through the examples in chapter 1 you'll
probably have found the *real* error in example 1-6: the statement
_tolower(ch)  should of course be  ch = _tolower(ch).


                                     Michiel

-- Michiel Koren               EARN/Bitnet:  s170miko@htikht5.BITNET
   Tilburg University          SURFnet:      kubvx1::s170miko
   Netherlands