Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!F.GP.CS.CMU.EDU!David.Detlefs
From: David.Detlefs@F.GP.CS.CMU.EDU
Newsgroups: gnu.g++.lib.bug
Subject: Bug in istream::get
Message-ID: <8908051856.AA21241@AENEAS.MIT.EDU>
Date: 5 Aug 89 18:56:13 GMT
Sender: daemon@tut.cis.ohio-state.edu
Distribution: gnu
Organization: GNUs Not Usenet
Lines: 47

I am using G++ 1.35 and libg++ 1.35.1.

Consider the following program:
--------------------------------------------------
#include <stream.h>

void main() {
  filebuf fin;
  fin.open("bug4-input", input);
  istream ist(&fin);
  char s[100];
  for (int i = 0; i < 50; i++) s[i] = '#';
  ist.get(s, 3);
  cout << "S is " << s << ".\n";
}
--------------------------------------------------

where 'bug4-input' is the file:

--------------------------------------------------
123456789
--------------------------------------------------

When compiled with G++ and libg++, this program prints

S is 1234.

Note that AT&T cfront (1.2.1 and a beta test of 2.0) do *not* print
what you might expect, which is

S is 123.

Instead, they print

S is 12.

An argument can be made that this is correct behavior, since
Stroustrup p. 237 says "... istream::get reads at most n characters
into a character vector starting at p [equivalent to s in this
program]."  Since get inserts the terminating null character in
addition to the characters read, "12\0" are the correct three
characters that should be put in s.

I am in the process of compiling and testing a fix, which I will post
if it works.

Dave