C# Signature:
[DllImport("kernel32.dll")]
static extern bool ReadFile(IntPtr hFile, byte[] lpBuffer,
uint nNumberOfBytesToRead, out uint lpNumberOfBytesRead, IntPtr lpOverlapped);
or
[DllImport("kernel32.dll", SetLastError=true)]
static extern unsafe int ReadFile(IntPtr handle, IntPtr bytes, int numBytesToRead,
IntPtr numBytesRead, NativeOverlapped* overlapped);
or
[DllImport("kernel32.dll", SetLastError=true)]
static extern bool ReadFile(IntPtr hFile, [Out] byte[] lpBuffer, uint nNumberOfBytesToRead,
out uint lpNumberOfBytesRead, [In] ref System.Threading.NativeOverlapped lpOverlapped);
User-Defined Types:
None.
Notes:
The documentation states that if using unbuffered IO, the memory must be "storage aligned" (aligned to the sector size of the storage device). Either this is not enforced, or managed allocations (specifically byte arrays) are automatically storage aligned because there seems to be no problem using it. Note that storage aligned and page aligned are not the same, and managed allocations are not in general page aligned (required for ReadFileScatter).
For more information on unbuffered IO in .NET see:
http://arxiv.org/abs/cs.PF/0502012
Tips & Tricks:
Please add some!
Sample Code:
Please add some!
Alternative Managed API:
System.IO.FileStream
See Also
WriteFile, WriteFileGather, ReadFileScatter
