troubles in making a filecopy program in visual c++

[Stlan]

Are you sure the files pathes are correct? It seems that "E:/data.txt" is very likely not a valid file name. You should use "E:\\data.txt" instead.

[David Crow]

firebolt77 wrote: ...when I run it, it generate an error and can't run. And what would that error be?

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"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

[David Crow]

firebolt77 wrote: n the program generate these errors: nafxcwd.lib(thrdcore.obj) : error LNK2001: unresolved external symbol __endthreadex nafxcwd.lib(thrdcore.obj) : error LNK2001: unresolved external symbol __beginthreadex Debug/excel.exe : fatal error LNK1120: 2 unresolved externals Error executing link.exe. Remove the /MT linker option.

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"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

[David Crow]

firebolt77 wrote: m_DataFile.Read(a,m_DataFile.GetLength); At this point, a is a NULL pointer. A crash is imminent. firebolt77 wrote: m_LogFile.Write(a,strlen(a)); This erroneously assumes that a will have a \0 character and that it will be at the end.

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"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

[firebolt77]

I already tried all the instructions, but still the program can't run. Although it doesn't generate error on compile process, but when I try to run it, it won't run. Here is my modified source code: int main() { CFile m_LogFile,m_DataFile; char* a=NULL; m_DataFile.Open("E:\\data.txt", CFile::modeRead|CFile::shareDenyNone); a = new char [m_DataFile.GetLength() + 1]; memset(a,0,m_DataFile.GetLength() + 1); try { m_LogFile.Open("E:\\data1.txt", CFile::modeWrite|CFile::modeRead|CFile::modeCreate|CFile::modeNoTruncate|CFile::shareDenyNone); m_LogFile.SeekToEnd(); } catch(CException* e) { e->ReportError(); e->Delete(); } m_DataFile.Read(a,m_DataFile.GetLength()); m_LogFile.Write(a,strlen(a)); m_DataFile.Close(); m_LogFile.Close(); return 0; }

[Stlan]

Execute step by step your program in debug mode, and check for the result value returned by the Open, Read, Write, etc. functions. You should then be able to locate where exactly is the problem.

[Bob Stanneveld]

No, he is using MFC, but he made a console application. So the default settings cause the linker not to link with the MFC libraries. He should change that setting to link dynamically or statically to the MFC. Behind every great black man...             ... is the police. - Conspiracy brother Blog[^]

[David Crow]

If that was the case, the linker would be complaining about MFC-related code instead of __endthreadex and __beginthreadex. See here for more.

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"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

[David Crow]

firebolt77 wrote: ...but when I try to run it... Which means what? Single-stepping through each statement, which one is not working?

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"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

[Joe Woodbury]

This code is not tested, I don't have the time, but here's a quick pass with comments. #include #include int main() { // Initialize MFC if (!AfxWinInit(::GetModuleHandle(NULL), NULL, ::GetCommandLine(), 0)) { _tprintf(_T("Fatal Error: MFC initialization failed\n")); return 1; } // m_ is a C++ convention to indicate a variabe is a data member // of a class. Also by convention, the first letter after the // underscore is lower case. For example, it would be m_logFile. // These are local variables, thus the m_ has been removed. CFile logFile, dataFile; // the char *a has been moved below, closer to where it is actually // being used. // The share mode should probably be deny write to prevent someone // from using while attempting other operations. dataFile.Open("E:/data.txt", CFile::modeRead|CFile::shareDenyWrite); // the try block is not needed since CFile::Open does not throw // an exception. (The CFile constructor throws an exception.) // Instead, we pass CFileException as a parameter and check the BOOL // return. // I also added ShareDenyWrite to prevent any other program from writing // to the file at the same time. CFileException err; if (!logFile.Open("E:/data1.txt", CFile::modeReadWrite|CFile::modeCreate|CFile::modeNoTruncate|CFile::shareDenyWrite, &err)) { // If I remember, this pops up a message box. For console apps // it's generally better to use _tprintf() or _tputs() err.ReportError(); return 1; } logFile.SeekToEnd(); // since we aren't using smart pointers for pBuffer, // this reduces having to add a delete before an // explicit error return. int rval = 0; // Allocate the buffer here. Note I used the convention of a p for // pointer. This is the extent of my general notation rules. int bufferLen = dataFile.GetLength(); char* pBuffer = new char[bufferLen]; if (dataFile.Read(pBuffer, bufferLen) == dataFile.GetLength()) { if (logFile.Write(pBuffer, bufferLen) != bufferLen) { _tprintf("Error writing file\n"); rval = 1; } } delete [] pBuffer; return rval; } Anyone who thinks he has a better idea of what's good for people than people do is a swine. - P.J. O'Rourke

[Christian Graus]

Thanks - I thought it was, but I did a google on CopyFile C++ and got no helpful links. Usually, MSDN is the first hit in a case like that. Christian Graus - Microsoft MVP - C++

[firebolt77]

I have tried the code(Mr. Joe Woodbury's code), but when I run it, it generate the same error with my code, although there is no error in the compile process.When I run the program, it generate a typical windows error dialog box(the one that has debug,send error report, and don't send button). I also try to debug it, but when I debug it, it opens other source code(winmain.cpp). I'm so confused. Pls help.. thx.

[Joe Woodbury]

Interesting, since it doesn't compile, you couldn't have tried my code. For one, you didn't include the right headers so the call to AfxWinInit would fail when compiling. Second you would need to declare an instance of CWinApp. Third CFile::Write() is a void function. The problem actually likely lies with the failure to check for failure with the dataFile.Open call if e:/data.txt doesn't exist or can't be otherwise opened. I simplified it and compiled the file below. An additional possibility is that your project is not set up correctly. So, before continuing, close the project and create a new one with Visual Studio. Assuming you are using VS 2003, On the File menu, click New and then Project. In the left pane, open Visual C++ Projects and the Win32 folder. In the right pane Select Win32 Console Project and enter a project name in the Name edit control, and then click OK. In the wizard, select Application Settings and then click the MFC checkbox in the right, and then "Finish." When the project opens, select everything in Main between the two outer braces, then paste the code below into it. Compile and run. Here is the code as I compiled in a console project:

if (!AfxWinInit(::GetModuleHandle(NULL), NULL, ::GetCommandLine(), 0))
{
	\_tprintf(\_T("Fatal Error: MFC initialization failed\\n"));
	return 1;
}

CFile logFile, dataFile;

CFileException err;

if (!dataFile.Open("e:/data.txt", CFile::modeRead | CFile::shareDenyWrite, &err))
{
	err.ReportError();
	return 1;
}

if (!logFile.Open("e:/data1.txt", CFile::modeReadWrite | CFile::modeCreate | CFile::modeNoTruncate | CFile::shareDenyWrite, &err))
{
	err.ReportError();
	return 1;
}
logFile.SeekToEnd();

int rval = 0;

int bufferLen = (int) dataFile.GetLength();
char\* pBuffer = new char\[bufferLen\];
if (dataFile.Read(pBuffer, bufferLen) == dataFile.GetLength())
{
	logFile.Write(pBuffer, bufferLen);
}
delete \[\] pBuffer;
return rval;

Anyone who thinks he has a better idea of what's good for people than people do is a swine. - P.J. O'Rourke

[Bob Stanneveld]

I sometimes used MFC in an application that was not linking to the MFC libraries. The only unresolved external symbols that I had were the __beginthreadex and __endthreadex. I thought that that was the problem, since he is using the CFile class from MFC. There are numerous ways to generate the same error, however. Behind every great black man...             ... is the police. - Conspiracy brother Blog[^]

[firebolt77]

I will try it. thx...