I want to asynchronously write data to file using WriteFileEx from winapi, but I have a problem with callback.
I'm getting follow error: an argument of type "void (*) (DWORD dwErrorCode, DWORD dwNumberOfBytesTransfered, LPOVERLAPPED lpOverlapped)" is incompatible with parameter of type "LPOVERLAPPED_COMPLETION_ROUTINE"
What am I doing wrong?
Here is code:
// Callback
void onWriteComplete(
DWORD dwErrorCode,
DWORD dwNumberOfBytesTransfered,
LPOVERLAPPED lpOverlapped) {
return;
}
BOOL writeToOutputFile(String ^outFileName, List<String ^> ^fileNames) {
HANDLE hFile;
char DataBuffer[] = "This is some test data to write to the file.";
DWORD dwBytesToWrite = (DWORD) strlen(DataBuffer);
DWORD dwBytesWritten = 0;
BOOL bErrorFlag = FALSE;
pin_ptr<const wchar_t> wFileName = PtrToStringChars(outFileName);
hFile = CreateFile(
wFileName, // name of the write
GENERIC_WRITE, // open for writing
0, // do not share
NULL, // default security
CREATE_NEW, // create new file only
FILE_FLAG_OVERLAPPED,
NULL); // no attr. template
if (hFile == INVALID_HANDLE_VALUE) {
return FALSE;
}
OVERLAPPED oOverlap;
bErrorFlag = WriteFileEx(
hFile, // open file handle
DataBuffer, // start of data to write
dwBytesToWrite, // number of bytes to write
&oOverlap, // overlapped structure
onWriteComplete),
CloseHandle(hFile);
}
You should start by reading the documentation carefully. This part is of particular import:
You are not meeting that requirement, and you need to tackle that issue urgently.
As for the compiler error, that's simple enough. Your callback does not meet the requirements. Again consult the documentation where its signature is given as:
You have omitted
CALLBACK
which specifies the calling convention.