Writing to file

[makaveliuk]

I am running a file copy routine i.e. CreateFile(), then a ReadFile() -> WriteFile() loop, but I want to write a few strings to the top of the file before the loop, how do I write the contents of a CString to the file with WriteFile()?

 

[obislavu]

CString str="abdc";
DWORD dw = 0;
OVERLAPPED os ;
// hFile obtained from CreateFile() and was not with FILE_FLAG_OVERLAPPED flag
BOOL bDone = WriteFile( hFile, (LPCVOID)str, str.GetLength(), &dw,NULL);
or
// hFile obtained from CreateFile() and with FILE_FLAG_OVERLAPPED flag
BOOL bDone = WriteFile( hFile, (LPCVOID)str, str.GetLength(), &dw,&os);
-obislavu-

 

[makaveliuk]

I tried that but I only get half the string in the file with null characters after each character.

What am I doing wrong?

 

[Skute]

try using

str.c_str()

instead of just "str"

Skute

"There are 10 types of people in this World, those that understand binary, and those that don't!"

 

[makaveliuk]

It says 'c_str' is not a member of CString when I try that.

 

[Skute]

sorry i was thinking of the STL string class.

Try:

str.GetBuffer(int Length)

That will give you a pointer to the actual buffer

Skute

"There are 10 types of people in this World, those that understand binary, and those that don't!"

 

[obislavu]

The following will create the C:\\text.txt file and if open it in notepad you will see :
abcd
George

CString str="abdc\r\n";
	CString str2="George\r\n";
	DWORD dw = 0;
	OVERLAPPED  os ;
	HANDLE hFile = CreateFile("C:\\test.txt",
   	GENERIC_WRITE,      
  	FILE_SHARE_WRITE,        
	NULL,
 	CREATE_NEW,  
  	FILE_ATTRIBUTE_NORMAL, 
  	NULL  );
	//hFile obtained from CreateFile() and was not with FILE_FLAG_OVERLAPPED flag
	BOOL bDone = WriteFile( hFile, (LPCVOID)str, str.GetLength(), &dw,NULL); 
	WriteFile( hFile, (LPCVOID)str2, str2.GetLength(), &dw,NULL); 
	//or
	// hFile obtained from CreateFile() and with FILE_FLAG_OVERLAPPED flag
	//BOOL bDone = WriteFile( hFile, (LPCVOID)str, str.GetLength(), &dw,&os); 
	CloseHandle(hFile);

-obislavu-

 

[makaveliuk]

Thanks for the code but it does the same thing, it looks okay when I open it in Wordpad but has null characters after each character when I open it in Wordpad or Hexedit.