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STL getline fails

Posted on 2002-06-28
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Last Modified: 2008-02-26
I'm using 'getline' for reading data from a file and writing it to another file.
like
  getline(inputFileObject,string,'\n')
It fails when there is occurance of the following character pattern
(\r\n\r\n\r\n)

0D 0A 0D 0A 0D 0A

characters. My OS is DYNIX/PTX (UNIX)

The same code works in VC++ 6.0.

Any idea?

(using 'strings' command and processing the input file works. but it looses format)


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Question by:prashant_n_mhatre
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Expert Comment

by:DanRollins
ID: 7117365
In what way does it fail?  I would expect it to return three empty strings.  What is it doing?

-- Dan
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Author Comment

by:prashant_n_mhatre
ID: 7117489
Here is the dump of the portion:

http://www.onesmartclick.com/books/dump.gif

It writes till '<html>' then doesn't write anything to file.

This is the test code I'm using:


void writeToFile(ifstream& inpFile)
{
    string refLine;
    ofstream fileout ("output.txt");
    while ( getline(inpFile,refLine,'\n') )
    {
        fileout << refLine;
        fileout << "\n";
    }
    fileout.close();
}

May be the code is buggy.

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Expert Comment

by:fl0yd
ID: 7123793
You should definately get rid of those constants, i.e. "\n" is bad -- the stl does have a replacement for that, that works across platforms: std::endl -- use this and see if it solves your problem.
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LVL 49

Expert Comment

by:DanRollins
ID: 7123920
It has something to do with the idiotic STL and namespace.  This sequence works because I waved a magic std wand over it:

#include <fstream>
#include <string>

void writeToFile( std::ifstream& inpFile )
{
     std::string refLine;
     std::ofstream fileout ("c:\\temp\\output.txt");
     while ( std::getline( inpFile, refLine, '\n' ) ) {
          fileout << refLine;
          fileout << "\n";
     }
     fileout.close();
}

void main()
{
     std::ifstream inpFile( "c:\\temp\\input.txt" );
     writeToFile(inpFile);
}

-- Dan
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Expert Comment

by:DanRollins
ID: 7128447
hi prashant_n_mhatre,
Do you have any additional questions?  Do any comments need clarification?
-- Dan
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Author Comment

by:prashant_n_mhatre
ID: 7128641
I tried out both options..nothing works... Works on Windows but doesn't work on DYNIX/PTX... Is it possible that stl library on DYNIX/PTX is buggy?
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Expert Comment

by:DanRollins
ID: 7128744
>> Is it possible that stl library on DYNIX/PTX is buggy?

It is possible.  But I ask that you try the sequence I provided, without change of any kind... it is a complete program.  Verify that it fails *only* when the input file has exactly four sequential sets of 0x0d 0x0a bytes.  Does it also fail with three or two in a row?

You might also want to try opening the file in binary mode (that was my first guess, but I stopped short of that when I got my sample working).

-- Dan
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Author Comment

by:prashant_n_mhatre
ID: 7132069
It doesn't compile on my machine. It says

"dan.cpp", line 8: error #304: no instance of overloaded function
          "std::getline" matches the argument list
            argument types are: (std::ifstream, std::string, char)
                        while ( std::getline( inpFile, refLine, '\n' ) ) {
                                ^

1 error detected in the compilation of "dan.cpp".
c++: Fatal Error: Compilation failed
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Accepted Solution

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DanRollins earned 50 total points
ID: 7132574
The compiler must be buggy.  The first param is a std::ifstream, the second param is a std::string, and the third parm is a char.  So the error message is bogus.  Stick to VC++ Its the only compiler worth using.

-- Dan
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Author Comment

by:prashant_n_mhatre
ID: 7165544
Yep..I also think so..Thanks for your help !!!
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