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data file help
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Join Date: May 2003
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Originally Posted by gilgamesh
i need to be able to add data to my .dat file without deleting my old data during a program run can anyone help me?
If this is a console app (DOS program) or UNIX program that outputs to standard output, you could redirect the output to your data file
program.exe >> datafile.dat
If this is a Windows program, you can use CreateFile with the following arguments
C Syntax (Toggle Plain Text)
HANDLE hFile = INVALID_HANDLE_VALUE; hFile = CreateFile("yourfile.dat", GENERIC_READ | GENERIC_WRITE, 0, // no file sharing NULL, // no security descriptor OPEN_ALWAYS, // creates if not found FILE_ATTRIBUTE_NORMAL, NULL); // No template handle
This returns a HANDLE that you can pass to ReadFile and WriteFile
Using SetFilePointer if you need to position to any part of the file.
C Syntax (Toggle Plain Text)
if (hFile != INVALID_HANDLE_VALUE) { DWORD bytesWritten; if (FALSE == WriteFile(hFile, dataBuffer, // data to write dataBufferSize, &bytesWritten, NULL)) // not using overlapped I/O { MessageBox(GetActiveWindow(), "Error", "Error", MB_ICONSTOP); } // will want to verify // bytesWritten == dataBufferSize }
Be sure to close the file with
C Syntax (Toggle Plain Text)
CloseHandle(hFile);
Hope this helps.
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