Bug 31901 - bad_cast when using copy on istreambuf_iterator<unsigned char>
bad_cast when using copy on istreambuf_iterator<unsigned char>
Status: RESOLVED INVALID
Product: gcc
Classification: Unclassified
Component: libstdc++
4.1.1
: P3 normal
: ---
Assigned To: Not yet assigned to anyone
:
Depends on:
Blocks:
  Show dependency treegraph
 
Reported: 2007-05-11 19:03 UTC by batterseapower
Modified: 2007-05-11 20:22 UTC (History)
2 users (show)

See Also:
Host: i686-pc-linux-gnu
Target: i686-pc-linux-gnu
Build: /var/tmp/portage/sys-devel/gcc-4.1.1-r3/work/gcc-4.1.1/configure
Known to work:
Known to fail:
Last reconfirmed:


Attachments
Preprocessed C++ source code for my test application (807.10 KB, text/plain)
2007-05-11 19:04 UTC, batterseapower
Details

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Description batterseapower 2007-05-11 19:03:43 UTC
When I try and "copy" a basic_ifstream<uint8_t> into a vector<uint8_t> I recieve a bad cast exception. If the uint8_t is replaced with "unsigned char" explicitly the problem persists, but if it is replaced with "char" the problem goes away.

This has been confirmed not only on my system (GCC 4.1.1), but an Ubuntu system running GCC 4.0.3 and another running GCC 4.1.2.

The code compiles and works fine under Microsoft Visual Studio .NET 2005. The g++ problem has not been tested on a Windows system.

------
#include <vector>
#include <iterator>

#include <fstream>
#include <iostream>
#include <sstream>

#ifndef WIN32
#include "stdint.h"
#else
typedef unsigned char       uint8_t;
#endif

using namespace std;

int main(int argc, char **argv)
{
    if (argc != 2)
    {
        cout << "Usage: " << argv[0] << " <log filename>" << endl;
        return 1;
    }

    // Open the input file
    basic_ifstream<uint8_t> inputFile(argv[1], ios::binary);
    if (inputFile.fail())
    {
        cout << "Failed to open the input file" << endl;
        return 2;
    }

    // Read the file into a vector
    vector<uint8_t> inputData;
    istreambuf_iterator<uint8_t> inputDataStartIterator(inputFile), inputDataEndIterator;
    copy(inputDataStartIterator, inputDataEndIterator, back_inserter(inputData));
}

----
Command that triggers the bug:
g++ test.cpp
Comment 1 batterseapower 2007-05-11 19:04:49 UTC
Created attachment 13541 [details]
Preprocessed C++ source code for my test application
Comment 2 Paolo Carlini 2007-05-11 19:09:52 UTC
This is known and we decided time ago not to do anything about it (you can find something either in Bugzilla or in the libstdc++ mailing list): a portable use of fstream with anything != char and wchar_t requires in general writing a custom codecvt.