Re: unmanaged structure layout error

I'm not sure I understand.
The strings are really c-style null-terminated strings.  The size I'm using
is the actual length of the array including the null-terminated byte.  If
the string is shorter than the full length then the remainder bytes are
null.

I've also tried LPStr but that fails as well.

On Wed, Nov 11, 2009 at 1:36 PM, Peter vd Weerd <[email protected]> wrote:

> May be strings should be aligned at 8 byte boundary?
> Did you try that?
>
> ----- Original Message ----- From: "Mike Andrews" <
> [email protected]>
>
> To: <[email protected]>
> Sent: Wednesday, November 11, 2009 8:04 PM
>
> Subject: [ADVANCED-DOTNET] unmanaged structure layout error
>
>
>   I'm having a problem with an unmanaged structure.
>>
>> I'm getting this error message when the system tries to load the type:
>>
>> *Could not load type '_S' from assembly '...' because it contains an
>> object
>> field at offset 134 that is incorrectly aligned or overlapped by a
>> non-object field.*
>>
>> For the life of me I cannot figure this out why this is failing.
>> I've set the byte packing to 1 which means that there is no padding
>> between
>> bytes.  I've also explicitly specified each field offset.
>>
>> Below is the structure that I have declared.  It's only a partial
>> structure
>> and I removed all the properties for brevity.  Also there's more members
>> but
>> the last field is where the error is occurring.  Also, if I remove the
>> last
>> field it works.  When I add it back it fails.
>>
>> Any suggestions?
>>
>> Thanks,
>> Mike
>>
>> [StructLayout(LayoutKind.Explicit, CharSet = CharSet.Ansi, Pack = 1)]
>> private struct _S {
>>   [FieldOffset(0)]
>>   private System.Double _height;
>>   [FieldOffset(8)]
>>   private System.Double _width;
>>   [FieldOffset(16)]
>>   private System.Double _depth;
>>   [FieldOffset(24)]
>>   private System.Double _a;
>>   [FieldOffset(32)]
>>   [MarshalAs(UnmanagedType.ByValArray, SizeConst = 24)]
>>   private System.Byte[] _u1;
>>   [FieldOffset(56)]
>>   private System.UInt16 _number;
>>   [FieldOffset(58)]
>>   private System.UInt16 _d;
>>   [FieldOffset(60)]
>>   [MarshalAs(UnmanagedType.ByValArray, SizeConst = 4)]
>>   private System.Byte[] _u2;
>>   [FieldOffset(64)]
>>   [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 70)]
>>   private System.String _name;
>>   [FieldOffset(134)]
>>   [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 33)]
>>   private System.String _address1;
>>
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