Bug in framework 2.0

[Eyal Safran]

Hello,

I've tried to create a matching MMTIME struct in C# to pass to the
timeGetSystemTime DllImported method... here are my structs:

[StructLayout(LayoutKind.Sequential)]
public struct MMTIME
{
public uint wType;
[MarshalAs(UnmanagedType.Struct)]
public Union u;

[StructLayout(LayoutKind.Explicit)]
public struct Union
{
[FieldOffset(0)] public uint ms;
[FieldOffset(0)] public uint sample;
[FieldOffset(0)] public uint cb;
[FieldOffset(0)] public uint ticks;
[FieldOffset(0)] [MarshalAs(UnmanagedType.Struct)] public
SMPTE smpte;
[FieldOffset(0)] [MarshalAs(UnmanagedType.Struct)] public
MIDI midi;
}

[StructLayout(LayoutKind.Sequential)]
public struct SMPTE
{
public byte hour;
public byte min;
public byte sec;
public byte frame;
public byte fps;
public byte dummy;
public ushort pad;
}

[StructLayout(LayoutKind.Sequential)]
public struct MIDI
{
public uint songptrpos;
}
}

When I do:

Marshal.SizeOf(typeof(MMTIME.MIDI)); = 4
Marshal.SizeOf(typeof(MMTIME.SMPTE)); = 8
Marshal.SizeOf(typeof(MMTIME.Union)); I get:

Type 'Common.Structures.MMTIME+Union' cannot be marshaled as an
unmanaged structure; no meaningful size or offset can be computed.

I tried remarking from the Union struct, any 1 of the 2 structures
members, and when I remaked the MIDI structure, it passed the
Marshal.SizeOf.

on the other hand, if i Add to the MIDI structure another member (so
that the struct now contains more than 1 memebr) it also works,
example:

[StructLayout(LayoutKind.Sequential)]
public struct MIDI
{
public uint songptrpos;
public uint tmp;
}

my guess is a Marshal.SizeOf does not work on structs which contains
another struct with 1 member in it...

Best Regards,

Eyal Safran.