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From: rds95@leah.Albany.Edu ( Robert Seals)
Newsgroups: comp.sources.d
Subject: File access problem using ptc --
Message-ID: <490@leah.Albany.Edu>
Date: Thu, 27-Aug-87 12:45:28 EDT
Article-I.D.: leah.490
Posted: Thu Aug 27 12:45:28 1987
Date-Received: Sat, 29-Aug-87 09:47:47 EDT
Organization: The University at Albany, Computer Services Center
Lines: 71
Keywords: reset, pascal, ptc, um

Yo,
    There is a problem - I'm sure you've heard about it already - in
the otherwise wonderful ptc program posted to comp.sources.unix recently.
It doesn't handle files correctly. Both the C and Pascal versions do
the same thing. Perhaps I can illustrate...

program ptcbug(input, output, f);
var
    f: text;
    c: char;

begin
    reset(f, 'ptcbug.p');

    while not eof(f) do begin
	while not eoln(f) do begin
	    read(f, c);
	    write(c)
	end;
	readln(f);
	writeln
    end
end.

This is a reasonable program for 4.2 pc (did I say Ultrix?). It works, and
even produces the correct result. But when the translated program is
cc'ed, here is what happens...

% ptc <ptcbug.p >ptcbug.c
% cc ptcbug.c
"ptcbug.c", line 66: operands of : have incompatible types
"ptcbug.c", line 120: redeclaration of rewind

So, I tracked down the problem, and it is in the `reset' - but the whole
thing is done with macros, and upon expansion by cpp, here is what you get

{ ..... stuff ..... }

main()
{
	 (f).init = (f).init ? ( ((f).out && !(f).eoln) ? ( ( f).buf = ('\n'),  ( f).eoln = (( f).buf == '\n'), (void)fputc(( f).buf, ( f).fp), 0) : 0, rewind((f).fp)) : (((f).fp = Fopen( "ptcbug.p", Rmode)), 1), (f).eof = (f).out = 0,  (f).init = 1, (f).eoln = (((f).buf = fgetc((f).fp)) == '\n') ? (((f).buf = ' '), 1) : 0;
	while (! ((((f).init == 0) ? (  fread((char *)&(f).buf, sizeof((f).buf), 1,  (f).fp)) : 0, ((f).eof ? 1 : 		((((f).fp)->_flag&	00020)!=0))) ? (boolean)1 : (boolean)0)) {
		while (! ((f).eoln ? (boolean)1 : (boolean)0)) {
			c =  (f).buf,  (f).init = 1, (f).eoln = (((f).buf = fgetc((f).fp)) == '\n') ? (((f).buf = ' '), 1) : 0;
			 ( output).buf = (c),  ( output).eoln = (( output).buf == '\n'), (void)fputc(( output).buf, ( output).fp);
		}
		Getl(&f);
		 ( output).buf = ('\n'),  ( output).eoln = (( output).buf == '\n'), (void)fputc(( output).buf, ( output).fp);
	}
	exit(0);

{ ....... more stuff ........}

It's like, wow man, like I can't handle this action at all, ya no? So,
somewhere up in the first line, there is an error in : .
As far as the redefinition of rewind(), I am puzzled, because it puts
the definition at the very end of the new C program. Hmm.

Has anybody come up with anything that will make it work? Programs that
use stdin and out all work fine, and this is a real bummer drag,
because very few of my programs don't use files.

HELP
rob

Robert Seals
Atmospheric Sciences Research Center
Try this one: rob@asrcmv.albany.edu It might work...
This is more likely: ...leah.albany.edu!asrcmv!rob
Or just use "r"! Or follow the From: path.
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