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POWin 32 Writefile: Access Viloation and Error 1784
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copied!<p>Two problems with the below code. To begin, I have been scouring this and various other forums for answers to my 1784 error code and everything I've tried has failed. Two of the threads I've checked on stackoverflow are <a href="https://stackoverflow.com/questions/6537416/writefile-returning-error-1784">WriteFile returning error 1784</a> and <a href="https://stackoverflow.com/questions/11287901/blockwrite-i-o-error-1784">BlockWrite I/O Error 1784</a>. I've checked some others on this forum but I'm not remembering exactly what the are right now.</p> <p>I'm trying to save an array of structs to an empty binary file. The first problem is that I get an access violation if my size variable (nNumberOfBytesToWrite parameter) is anything less about 99000 bytes. That number jumps around. For awhile when I was testing it would have the access violation if it was 99,999 bytes but not 100,000 bytes. Of course, what I eventually want to do is set the size to the size of the entire array. The original code to handle that is now commented out so I can test with various sizes.</p> <p>The second thing that happens (if I don't get an access violation) is I get error code 1784 and WriteFile fails every time. As other threads on this topic have stated, this is defined on MSDN as ERROR_INVALID_USER_BUFFER and the description is "The supplied user buffer is not valid for the requested operation." I've looked at MSDN's own example for opening files like this (<a href="http://msdn.microsoft.com/en-us/library/windows/desktop/bb540534%28v=vs.85%29.aspx" rel="nofollow noreferrer">http://msdn.microsoft.com/en-us/library/windows/desktop/bb540534%28v=vs.85%29.aspx</a>) and have tried some variations based on their code, but nothing seems to work.</p> <p>This problem is probably massively noob and I'm sure I'm overlooking something ridiculously simple, but if anyone has suggestions they'd be greatly appreciated.</p> <pre><code>case IDM_SAVE1: { HANDLE hFile = CreateFile("MineSave.mss", GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL); int test_buffer[] = {1,2,3,4,5,6,7,8,9,10}; if(hFile != INVALID_HANDLE_VALUE) { BOOL bSuccess; DWORD size = 100000; //DWORD size = (((sizeof(tile)) * tiles_total)); LPDWORD bytes_written = 0; bSuccess = WriteFile(hFile, test_buffer, size, bytes_written, NULL); if(bSuccess) { MessageBox(hwnd, "File saved successfully.", "Great Job!", MB_OK); } else { DWORD error = GetLastError(); MessageBox(hwnd, "Could not write to file.", "Error", MB_OK); } CloseHandle(hFile); } else { MessageBox(hwnd, "Could not create file.", "Error", MB_OK); } } break; </code></pre>

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