engiGetAttrOptionalBN

This call can be used to check if an attribute is optional

Syntax

public const string ifcenginedll = @"ifcengine.dll";

[DllImport(IFCEngineDLL, EntryPoint = "engiGetAttrOptionalBN")]
public static extern Int64 engiGetAttrOptionalBN(Int64 entity, string attributeName);

[DllImport(IFCEngineDLL, EntryPoint = "engiGetAttrOptionalBN")]
public static extern Int64 engiGetAttrOptionalBN(Int64 entity, byte[] attributeName);    

Property entity

Size: 64 bit / 8 byte (value)
...

Property attributeName

Size: 64 bit / 8 byte (reference)
...