From:	Jack Klein <jackklein AT spamcop DOT net>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: compiler doesn't catch missing semicolon after struct
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Date:	Fri, 12 Oct 2001 03:43:27 GMT
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On Wed, 10 Oct 2001 12:43:57 -0400, Radical NetSurfer wrote in
comp.os.msdos.djgpp:

Don't top post, it's rude.  Fixed.

> On Tue, 09 Oct 2001 20:33:27 GMT, Martin Ambuhl
> <mambuhl AT earthlink DOT net> wrote:
> 
> >tenbux wrote:
> >> 
> >> Hi all,
> >> 
> >> I was working on a fairly simple lab for a CS class, and using DJGPP
> >> to compile and test my programs. Here is some sample code I had
> >> written:
> >> 
> >> #include <stdio.h>
> >> 
> >> struct bit {
> >>   int bit;
> >>   struct bit *next;
> >> }
> >> 
> >> main(int argc, char *argv[])
> >> {
> >>   int x;
> >>   FILE *in, *out;
> >> 
> >>   if (argc < 3) {
> >>     puts("Usage: binprint <numbers> <output>");
> >>     return;
> >>   }
> >> 
> >>   if ((in = fopen(argv[1], "r")) == NULL) {
> >>     printf("Error opening input file: %s\n", argv[1]);
> >>     return;
> >>   }
> >> 
> >> You'll notice that there is no semicolon after the struct declaration
> >> (as is required). But gcc didn't catch this, instead it warned me
> >> about main not being declared as int. 
> >
> >gcc caught it.  You declared main as returning a struct bit instead of
> >an int.  It told you about, but ...
> >
> >> So when I ran the binary with no
> >> arguments, 
> >
> >you ignored the warning and got what you deserved.
> >
> >> Is this a current bug or is it supposed
> >> to act that way? :)
> >
> >Don't blame the compiler for your errors.

> GCC does some very nice Syntax Checking
> (more than some compilers do)

It's not a syntax error.  It's undefined behavior, but syntactically
perfectly correct.

-- 
Jack Klein
Home: http://JK-Technology.Com
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