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From: battle@alphard.cs.utk.edu (David Battle)
Newsgroups: comp.lang.c,comp.std.c
Subject: Bug in DEC's C compiler(s)
Summary: objects declared as "void *" are called "undefined" by compiler
Message-ID: <1528@utkcs2.cs.utk.edu>
Date: 2 Jan 90 17:59:14 GMT
Sender: news@utkcs2.cs.utk.edu
Reply-To: battle@alphard.cs.utk.edu (David Battle)
Followup-To: comp.lang.c
Organization: CS Dept -- University of TN, Knoxville
Lines: 78
Keywords:

I seem to have discovered a bug in DEC's Ultrix C compilers.  The bug
exhibits itself on both vax and mips architectures.  The problem is that
it seems to ignore objects declared as "void *".  Here is an example,
straight out of K&R2 (page 121):

First, on a DECStation 3100:

mips> head -1 /etc/motd
Ultrix Worksystem V2.1 (Rev. 14) System #2: Mon Nov  6 11:22:25 EST 1989
mips> cat tmp.c
void
swap(void *v[], int i, int j)
{
    void *temp;

    temp = v[i];
    v[i] = v[j];
    v[j] = temp;
}
mips> cc -c tmp.c
ccom: Error: tmp.c, line 6: temp undefined
          temp = v[i];
      ---------^
ccom: Warning: tmp.c, line 6: illegal combination of pointer and integer, op =
          temp = v[i];
      ---------------^
ccom: Warning: tmp.c, line 8: illegal combination of pointer and integer, op =
          v[j] = temp;
      ---------------^
(ccom): tmp.c, line 8: cannot recover from earlier errors: goodbye!
      }
      ^

And on the MicroVax (doesn't handle prototypes yet):

vax> head -1 /etc/motd
Ultrix-32 V3.0 (Rev 64) UWS V2.0 System #2: Fri Aug  4 00:02:44 EDT 1989
vax> more foo.c
void
swap(v,i,j)
void *v[];
int i, j;
{
    void *temp;

    temp = v[i];
    v[i] = v[j];
    v[j] = temp;
}
vax> cc -c foo.c
"foo.c", line 8: temp undefined
"foo.c", line 8: warning: illegal combination of pointer and integer, op =
"foo.c", line 10: warning: illegal combination of pointer and integer, op =


The unprotoized version works fine on a sun:

sun> cat > foo.c
swap(v,i,j)
void *v[];
int i, j;
{
    void *temp;

    temp = v[i];
    v[i] = v[j];
    v[j] = temp;
}
sun> cc -c foo.c
sun>


Am I missing something here, or is this a real bug?


					-David L. Battle
					 battle@battle.esd.ornl.gov
					 battle@utkux1.utk.edu