OffsetOf

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OffsetOf

Returns the offset of a field within a type.

Syntax

#define OffsetOf(typename, fieldname) CInt( @Cast( typename Ptr, 0 )->fieldname )

Usage

result = OffsetOf( typename, fieldname )

Parameters

typename

Name of the type as defined using the Type...End Type statements.

fieldname

Name of the field as defined within the type (or within the base types for a derived type).

Description

For a non-derived type, OffsetOf will return the location fieldname as offset in bytes from the beginning of typename.

For a derived type, OffsetOf will return the location fieldname as offset in bytes from the beginning of its highest base type.
Note: if a member of the base type is overridden by a new member, the offset of the old member cannot be accessed from the derived type.

Example

Type MyType x As Single y As Single Union b As Byte i As Integer End Union End Type Print "OffsetOf x = "; OffsetOf(MyType, x) Print "OffsetOf y = "; OffsetOf(MyType, y) Print "OffsetOf b = "; OffsetOf(MyType, b) Print "OffsetOf i = "; OffsetOf(MyType, i)

Output

OffsetOf x =  0
OffsetOf y =  4
OffsetOf b =  8
OffsetOf i =  8

Dialect Differences

Not available in the -lang qb dialect unless referenced with the alias __Offsetof.

Differences from QB

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