INFO: LenB Returns in-Memory Size of User-Defined Type

• Standard, Professional, and Enterprise Editions of Microsoft Visual Basic, 32-bit only, for Windows, version 4.0

SUMMARY

LenB function returns the in-memory size of a user-defined type (UDT).

MORE INFORMATION

Visual Basic 32-bit structures are DWORD aligned (four bytes) when stored in memory. Fixed-length strings use two bytes for every character to account for UNICODE. String descriptors use four bytes each. Integers use two bytes. Please refer to the Visual Basic Help file for the lengths of all the other data types.

Example One

Consider this example UDT:

   Type Generic
     FirstName as String * 5
     LastName as String
     ChildrenAges (1 to 5) as Byte
   End Type

• FirstName uses 10 bytes (UNICODE).
• LastName uses 4 bytes (String descriptor).
• ChildrenAges uses 5 bytes (5-element byte array).

• 8 bytes for the first 8 bytes of FirstName.
• 8 bytes for the last 2 bytes of FirstName, 2 bytes of padding, 4 bytes for LastName.
• 5 bytes for the 5 bytes needed for ChildrenAges.

   LenB(Generic) = 21
   Len (Generic) = 14

Example Two

Consider this example UDT:

   Type Generic
     FirstName as String * 7
     LastName as String * 6
     ChildrenAges (1 to 5)  as Byte
     Address * String
   End Type

• FirstName uses 14 bytes (UNICODE).
• LastName uses 12 bytes (UNICODE).
• ChildrenAges uses 5 bytes (5-element byte array).
• Address uses 4 bytes (string descriptor)

• 8 bytes for the first 8 bytes of FirstName.
• 8 bytes for the last 6 bytes of FirstName, 2 bytes of padding, 2 bytes for LastName.
• 8 bytes for the next 8 bytes of LastName.
• 8 bytes for the last 2 bytes of LastName, 5 bytes for ChildrenAges, and 1 byte of padding.
• 4 bytes for Address for the string descriptor.

   LenB(Generic) = 36
   Len (Generic) = 22

Keywords          : PrgOther vb432 VB4WIN vbwin GnrlVb kbenv kbprg
Technology        : kbvba
Version           : WINDOWS:4.0
Platform          : WINDOWS
Issue type        : kbinfo