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From: leech@phi.cs.unc.edu (Jonathan Leech)
Newsgroups: comp.lang.c++
Subject: Interesting bug in cfront 1.2.1
Message-ID: <4483@thorin.cs.unc.edu>
Date: 3 Oct 88 01:40:32 GMT
Sender: news@thorin.cs.unc.edu
Reply-To: leech@phi.cs.unc.edu (Jonathan Leech)
Organization: University Of North Carolina, Chapel Hill
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    The following code demonstrated an interesting problem I
encountered with cfront 1.2.1: under certain conditions, an old-style
function definition will not match a (correct) prototype declaration.

    // tst.c
    char *_ent_char( int, char *, char *, int );

    char *_ent_char(i, p, q, j)
    int i;
    #ifdef BUG
    char *p, *q;
    #else
    char *p;
    char *q;
    #endif
    int j;
    {
	return(p);
    }

    Script started on Sun Oct  2 21:34:22 1988
    % CC -c tst.c
    "tst.c", line 3: warning: old style definition of _ent_char()
    "tst.c", line 14: warning:	i not used
    "tst.c", line 14: warning:	q not used
    "tst.c", line 14: warning:	j not used
    % CC -c -DBUG tst.c
    "tst.c", line 3: warning: old style definition of _ent_char()
    "tst.c", line 14: error:  _ent_char() type mismatch: char *(int , char *, char *, int ) and char *(int , char *, int , int ... )
    1 error
    % ^D
    script done on Sun Oct  2 21:34:58 1988

    Obviously this is easy to code around - don't post followups on
how to do so!

    This came up when trying to run cfront over a 25000 line old C
program as an enhanced version of lint. I don't recommend this
procedure for the faint at heart since cfront is not truly downwards
compatible with old C code.
--
    Jon Leech (leech@cs.unc.edu)    __@/
    ``Are there any more questions, besides the ones from the
      liberal communists?''
	- George Uribe, natl. director of "Students For America"