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Behavior of ifstream::read()
From: |
Alex Vinokur |
Subject: |
Behavior of ifstream::read() |
Date: |
Sat, 14 Oct 2006 16:27:29 +0200 |
This program has different behavior in
* g++ 3.4.4 (Cygwin)
* gpp 4.0.1 *Djgpp)
* Microsoft C++ 13.00.9466
------- foo.cpp ------
#include <iostream>
#include <iomanip>
#include <fstream>
using namespace std;
#define BUFFER_SIZE 1500
#define INPUT_FILE_NAME "in.txt"
void foo ()
{
char cbuffer[BUFFER_SIZE];
ifstream fs (INPUT_FILE_NAME);
fs.clear();
fs.seekg (0, ios::beg);
while (!fs.eof())
{
fs.read (cbuffer, sizeof(cbuffer));
cout << "rdstate() = 0x" << hex << fs.rdstate() << dec << "; gcount() = "
<< fs.gcount() << endl;
}
cout << "rdstate() = 0x" << hex << fs.rdstate() << dec << endl;
}
int main ()
{
foo ();
return 0;
}
----------------------
Test input file can be seen at
http://groups.google.com/group/test-av/msg/0c4d3da487594ab7
Output for g++ (Cygwin)
--------------------
rdstate() = 0x6; gcount() = 1499
rdstate() = 0x6
-------------------
It seems that behavior of g++ is wrong here.
Output for gpp (Djgpp)
-------------------
rdstate() = 0x0; gcount() = 1500
rdstate() = 0x0; gcount() = 1500
rdstate() = 0x0; gcount() = 1500
rdstate() = 0x0; gcount() = 1500
rdstate() = 0x0; gcount() = 1500
rdstate() = 0x6; gcount() = 1071
rdstate() = 0x6
-------------------
Output for Microsoft C++
-------------------
rdstate() = 0x0; gcount() = 1500
rdstate() = 0x0; gcount() = 1500
rdstate() = 0x0; gcount() = 1500
rdstate() = 0x0; gcount() = 1500
rdstate() = 0x0; gcount() = 1500
rdstate() = 0x3; gcount() = 1071
rdstate() = 0x3
-------------------
--
Alex Vinokur
email: alex DOT vinokur AT gmail DOT com
http://mathforum.org/library/view/10978.html
http://sourceforge.net/users/alexvn
- Behavior of ifstream::read(),
Alex Vinokur <=