Xref: news2.mv.net comp.os.msdos.djgpp:3793
From: Dieter Demerre <Dieter DOT Demerre AT cs DOT kuleuven DOT ac DOT be>
Newsgroups: comp.os.msdos.djgpp
Subject: bug in fstream ? (V2) for in-out files ?
Date: Mon, 13 May 1996 16:27:13 +0200
Organization: K.U.Leuven
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Message-ID: <319746C1.41C67EA6@cs.kuleuven.ac.be>
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CC: Dieter DOT Demerre AT cs DOT kuleuven DOT ac DOT be
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

A couple of months ago I installed DJGPP for I wanted to compile
my program with it.  Just last weekend I found that not all objects
behave like they do in BC3.1.
I hereby include my testprogram (partly)  that tries to read from
a file but also write to it.

I find that whenever I open the file to write in it, the file is
renewed, while this is NOT done in Borland C++ nor in 
the C++ compiler we have here on the VAX- and ALPHA-machines.

Did I do anything wrong ?

// filename: filetest.cpp
// date    : 1996-05-13
// descript: Will create a file if it does not exist yet,
//           will write at the end, read at the beginning,
//           write at the end, write at the beginning
//           write at the end.
#include <iostream.h>
#include <fstream.h>

int main()
{
        fstream a_stream;
        char st[200];

        a_stream.open("test.fil",ios::in|ios::out|ios::nocreate|ios::ate);
        cout << "test.fil in-out-opened" << endl;
        if (!a_stream.good()) {
                a_stream.open("test.fil",ios::out);
                a_stream.close();
                a_stream.open("test.fil",ios::in|ios::out|ios::ate);
        };
        if (a_stream.good()) {
                a_stream << "Test this file." << endl;
                a_stream.seekg(0,ios::beg);
                a_stream >> st;
                a_stream.seekp(0,ios::end);
                a_stream << "this file has an end." << endl;
                a_stream.seekg(0,ios::beg);
                a_stream << "begin" << endl;
                a_stream.seekp(0,ios::end);
                a_stream << "end test" << endl;
		a_stream << "beginning had \"" << st << "\"" << endl;
                a_stream.close();
        } else {
                cout << "a_stream cannot be created" << endl;
        };
        return 0;
};


Greetings from = Groetjes vanwege
--------------------------------------------
Dieter Demerre
Email : Dieter DOT Demerre AT cs DOT kuleuven DOT ac DOT be
http  : www.cs.kuleuven.ac.be/~demerre
--------------------------------------------