Instance Header API Calls
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Schema Reading API Calls
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Instance Writing API Calls
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Uncategorized API Calls
Geometry Kernel related API Calls
Deprecated API Calls (GENERIC)
Validation
Deprecated API Calls (GEOMETRY)

engiGetAttrOptionalBN

This call can be used to check if an attribute is optional. Technically engiGetAttrOptionalBN will transform into the following call

    engiGetAttrOptional(
            sdaiGetAttrDefinition(
                    entity,
                    attributeName
                )
        );

Syntax

C++ 32 bit
C++ 64 bit
C# 32 bit
C# 64 bit
public const string ifcenginedll = @"ifcengine.dll";

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

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

Property entity

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

Property attributeName

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