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See this thread.
"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown
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hi all..I'm newbie in visual c++ and I'm trying to make a simple file copy program, but it doesn't work. Here is my source code:
#include<afx.h>
#include<stdio.h>
int main()
{
CFile m_LogFile,m_DataFile;
char* a=NULL;
m_DataFile.Open("E:/data.txt", CFile::modeRead|CFile::shareDenyNone);
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));
return 0;
}
The message error said that the m_DataFile.Read(a,m_DataFile.GetLength); part is wrong, but when I change the 2nd parameter into fixed number(I tried 10 and 100), it generate other error. Can somebody help me?
thx
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I can't find it, but there is most certainly an API call you can make to copy a file, if you want to. In the meantime, m_DataFile.GetLength is a function pointer. m_DataFile.GetLength() is a function call.
Christian Graus - Microsoft MVP - C++
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It is CopyFile(...)
Einstein: "Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe."
My Articles
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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++
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1- Change m_DataFile.Read(a,m_DataFile.GetLength); to:
m_DataFile.Read(a,m_DataFile.GetLength());
because GetLength() is a function.
2- And also, you are using char* a = NULL;
You are not assigning any memory to it. It is a null pointer.
You can try this:
char* a = NULL;
a = m_DataFile.GetLength() + 1;
memset(a,0,m_DataFile.GetLength()+1);
Then read the file into it:
m_DataFile.Read(a,m_DataFile.GetLength());
this is this.
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I already change the source code..but it is still error. This is my source code:
#include<afx.h>
#include<stdio.h>
#include<memory.h>
int main()
{
CFile m_LogFile,m_DataFile;
char* a=NULL;
m_DataFile.Open("E:/data.txt", CFile::modeRead|CFile::shareDenyNone);
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();
}
memset(a,0,m_DataFile.GetLength()+1);
m_DataFile.Read(a,m_DataFile.GetLength());
m_LogFile.Write(a,strlen(a));
return 0;
}
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.
excel.exe - 3 error(s), 0 warning(s)
n I don't understand what it's means...pls help.
thx
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If you're using VC 6. do the following:
Menu item Project->Settings->Tab C++ -> Category 'Code Generation'->
set this option to 'Multithreaded' or 'Debug Multithreaded'
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I already change the code generation into multithreaded. The program can be compiled successfully but when I run it, it generate an error and can't run. Give me some hints please. Is there any logic error on my program?
The reason that I didn't use CopyFile is if the program works, I'm planning to make a program that can make XML file from text file which I think it can't be done using CopyFile function.
thx.
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firebolt77 wrote:
...when I run it, it generate an error and can't run.
And what would that error be?
"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown
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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.
"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown
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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[^]
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If that was the case, the linker would be complaining about MFC-related code instead of __endthreadex and __beginthreadex . See here for more.
"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown
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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[^]
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A simple trick - when you want to see if a function exists to do something go Help->Index and try typing in possible function names. As you type more letters it narrows the results.
"Filecopy" didn't return anything but "Copyfile" returned
CopyFile(LPCTSTR lpExistingFileName, LPCTSTR lpNewFileName, BOOL bFailIfExists)
Elaine
The tigress is here
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I already change the code generation into multithreaded. The program can be compiled successfully but when I run it, it generate an error and can't run. Give me some hints please. Is there any logic error on my program?
The reason that I didn't use CopyFile is if the program works, I'm planning to make a program that can make XML file from text file which I think it can't be done using CopyFile function.
thx.
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I am soooo sorry that I mis-wrote a line in my earlier post:
a = m_DataFile.GetLength() + 1;//error. Do not use.
Should have been:
a = new char [m_DataFile.GetLength() + 1]; //This one will do the thing.
this is this.
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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.
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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;
}
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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.
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firebolt77 wrote:
...but when I try to run it...
Which means what? Single-stepping through each statement, which one is not working?
"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown
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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.
"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown
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This code is not tested, I don't have the time, but here's a quick pass with comments.
<br />
#include<afx.h><br />
#include<stdio.h><br />
<br />
int main()<br />
{<br />
if (!AfxWinInit(::GetModuleHandle(NULL), NULL, ::GetCommandLine(), 0))<br />
{<br />
_tprintf(_T("Fatal Error: MFC initialization failed\n"));<br />
return 1;<br />
}<br />
<br />
CFile logFile, dataFile;<br />
<br />
<br />
dataFile.Open("E:/data.txt", CFile::modeRead|CFile::shareDenyWrite);<br />
<br />
<br />
CFileException err;<br />
if (!logFile.Open("E:/data1.txt", CFile::modeReadWrite|CFile::modeCreate|CFile::modeNoTruncate|CFile::shareDenyWrite, &err))<br />
{<br />
<br />
err.ReportError();<br />
return 1;<br />
}<br />
logFile.SeekToEnd();<br />
<br />
int rval = 0;<br />
<br />
int bufferLen = dataFile.GetLength();<br />
char* pBuffer = new char[bufferLen];<br />
if (dataFile.Read(pBuffer, bufferLen) == dataFile.GetLength())<br />
{<br />
if (logFile.Write(pBuffer, bufferLen) != bufferLen)<br />
{<br />
_tprintf("Error writing file\n");<br />
rval = 1;<br />
}<br />
}<br />
delete [] pBuffer;<br />
return rval;<br />
}<br />
Anyone who thinks he has a better idea of what's good for people than people do is a swine.
- P.J. O'Rourke
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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.
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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
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