Odd size of struct

[Morten Wennevik]

Hi,

Using a struct like the following, Marshal.SizeOf always reports 14 bytes yet the struct should be 13 bytes.
What am I doing wrong?

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public struct GIF_HEADER
{
[MarshalAs(UnmanagedType.ByValArray, SizeConst=3)]
public byte[] Signature; // Header Signature (always "GIF")
[MarshalAs(UnmanagedType.ByValArray, SizeConst=3)]
public byte[] Version; // GIF format version ("87a" or "89a")
public UInt16 ScreenWidth; // width in pixels
public UInt16 ScreenHeight; // height in pixels
public byte Packed; // screen and color map information
public byte BackgroundColor; // background color index
public byte AspectRatio; // pixel aspect ratio
}

Morten

[cody]

Try to use SizeConst=13 or Pack=1 in the StructLayout Attribute to ensure no
internal struct padding is done.

--
cody

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"Morten Wennevik" <Mo************@hotmail.com> schrieb im Newsbeitrag
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Hi,

Using a struct like the following, Marshal.SizeOf always reports 14 bytes yet the struct should be 13 bytes. What am I doing wrong?

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public struct GIF_HEADER
{
[MarshalAs(UnmanagedType.ByValArray, SizeConst=3)]
public byte[] Signature; // Header Signature (always "GIF")
[MarshalAs(UnmanagedType.ByValArray, SizeConst=3)]
public byte[] Version; // GIF format version ("87a" or "89a")
public UInt16 ScreenWidth; // width in pixels
public UInt16 ScreenHeight; // height in pixels
public byte Packed; // screen and color map information
public byte BackgroundColor; // background color index
public byte AspectRatio; // pixel aspect ratio
}

Morten