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FNREAD macro
The FNREAD macro provides the declaration for the application-defined callback function to read data from a file in an FDI context.
Syntax
void FNREAD( [in] INT_PTR hf, [out] void FAR *pv[bcount(cb)], UINT cb );
Parameters
- hf [in]
-
An application-defined value used to identify the open file.
- pv [out]
-
Pointer to the buffer that receives the data read from a file.
- cb
-
The maximum number of bytes to be read.
Return value
The indicated callback function returns the number of bytes read. However, a value of -1 indicates an error.
Remarks
The function accepts parameters similar to _read.
Examples
FNREAD(fnFileRead)
{
DWORD dwBytesRead = 0;
if ( ReadFile((HANDLE)hf, pv, cb, &dwBytesRead, NULL) == FALSE )
{
dwBytesRead = (DWORD)-1L;
}
return dwBytesRead;
}
Requirements
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Header |
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See also
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