Re: Problem with ios::flags

From:
John Harrison <john_andronicus@hotmail.com>
Newsgroups:
comp.lang.c++
Date:
Fri, 15 Jun 2007 06:37:39 GMT
Message-ID:
<Tsqci.6624$O%6.4880@newsfe6-gui.ntli.net>
Paulo da Silva wrote:

Hi!
Please consider the following fragment

      std::cin.exceptions(std::ios::failbit);
...
      try
      { is.getline(p,ILEN);
        ...
      }
      catch (std::ios::failure const &problem)
      { if (WHAT HERE?)
        { // '\n' not found yet
    }
        else
        { // Real failure
        }
      }

How do I tell a real failure from just ILEN-2 chars already read but not
yet '\n'?

Thanks for any help.


You mean ILEN-1 chars. If the fail bit is set there will either be
ILEN-1 chars or zero chars (not counting the null terminator) in p. So
you can test for that.

if (strlen(p) == ILEN-1)
{
}
else
{
}

Here's a good site that explains exactly what istream::getline does.

http://www.dinkumware.com/manuals/default.aspx?manual=compleat&page=istream.html#basic_istream::getline

It you haven't considered it already you should defintely think about
switching to the string version of getline

http://www.dinkumware.com/manuals/default.aspx?manual=compleat&page=string2.html#getline

Might be no need to treat long lines as a special case then.

john

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