Solution
A reference number (refnum) is a structure used to identify and recover some operation that has been performed inside LabVIEW.
The general structure of the refnum is :
[length] [type code] [type code for specific refnum] [specific type code information] [number of characters in label] [label characters]The description of the number is (in hexadecimal format):
- [length]
Number of bytes that exist in this datatype - [type code]
7030 - Code for refnums - [type code for specific refnum]
01 - Data Log File or a GOOP (Graphical Object-Oriented Programming) refnum
02 - Byte Stream File
04 - Occurrence
05 - TCP/IP Network Communication
07 - Activex Automation
08 01 00- Application VI
08 02 04 00 - VI Refnum
08 06 04 00 - Control
09 - Menu
0E - Visa Resource Name
0F - IVI Logical Name
10 - UDP Network Communication
11 - Notification*
12 - Queue* - [specific type code information]
The code in this area is specific for each refnum. Please check on the link below for further information. - [number of characters in label] and representative [label characters]
(*) Note: The new refnums for Notification and Queue are a new kind of refnum implemented in LabVIEW 6.1. In older versions, they appear as type code 01 (GOOP refnum).
If you are interested in obtaining some specific information for a refnum, you can follow these instructions:
7.x or earlier
1. Create a Control Refnum on the front panel of a VI.
2. Create a Property Node and select Type Descriptor.
3. Create an Indicator for the property node and examine the results after you execute the program.
You will be able to see the composition of type descriptor examining the array obtained with TypeDesc.
8.x and later
The Type Descriptor property node was dropped in later versions of LabVIEW.