Question

I’m coding a class that should read OFF Files and I’m having the following issue:

If I compile it within the Code::Blocks environment everything works fine.
If the first line of the file that is to be loaded differs from “OFF” it will jump into the second if-statement and exit the program…

However if I compile with g++ in cygwin the program jumps into the second if-Statement no matter what is actually written in the file.
Any Suggestions?

#include <stdlib.h>
#include <iostream>
#include <fstream>
#include <sstream>
#include <string>

polyeder offManager::readOFF(std::string filename)
{
    //Open File
    std::ifstream file(filename.c_str());

// If file couldn't be opened
if( !file.is_open() )
{
    std::cerr << "ERROR: Konnte Datei \""
    << filename << "\" nicht oeffnen!"
    << std::endl;
    exit (2);
}


// Test if the file really is an OFF File
std::string line;
std::string off ("OFF");
getline( file, line );
if ( line.compare(off) != 0 )
{
    std::cerr << "ERROR: Datei \""
    << filename << "\" ist nicht im OFF Format!"
    << std::endl;
    file.close();
    exit (2);
}
...
}

If I type g++ -v in cygwin I get the following:
Blablabla
Thread-Modell: posix
gcc-Version 4.5.3 (GCC)

Code::Blocks uses this version:
Thread model: win32
gcc version 4.4.1 (TDM-2 mingw32)

Answer 1

The file you are opening is likely in DOS text format, so it’s lines end with \r\n, rather than just \n.

The Cygwin FAQ has an entry about this issue. I copied your code into a simple main driver, and compiled it two ways. First, the regular way:

$ g++ s.cc
$ ./a.exe test
ERROR: Datei "test" ist nicht im OFF Format!

And then, with the suggested fix (open with text translation mode, write with binary mode):

$ g++ s.cc /usr/lib/automode.o 
$ ./a.exe test