Buffer alignment

[sinsi]

I was looking at ReadDirectoryChangesW and came across something I've not seen in the MS documentation.

[out] lpBuffer
A pointer to the DWORD-aligned formatted buffer in which the read results are to be returned.

I thought Windows was pretty relaxed about buffer alignment, but later

ReadDirectoryChangesW fails with ERROR_NOACCESS when the buffer is not aligned on a DWORD boundary.

Wonder why align 4 is so important?

[Greenhorn]

The alignment is important because the FILE_NOTIFY_INFORMATION structure is variable in length, because of it's last member FileName.

The other structure members are DWORDs, so you must align at 4 bytes (at least?).

8 byte and 16 byte alignment should also work ?! But this is just a guess by myself.