What cast type are used for?

Question

In the example attached to this question is a simple VI application that cast, using type cast of LabVIEW, one value to different other type. My understanding of type cast, in C, C++ and to my best knowledge, was an implicit adaptation of a numerical value in a specific format to an other format. The value should remain the same. Unless the type in which the value is assigned is not enough large or adapted to contain such a number ex:
I8 = 500;
U32 = -1;
But in my example all the assigned indicator are large enough.
I have the same problem in LabVIEW 5.1.1 and 6.1
If someone could only tell me what it is used for?
Best regards,
Nitrof
Attachments:
Type_cast.vi ‏26 KB

Answer 1

The type cast function is really helpful for typecasting "unusual" data to a more convienient data format. It can also be used to coerce data, like in your example, but coercion is usually not always a good thing because it can cause bad values.
There are lots of good examples of typecasting.
For example, I use the typecast function to change refnums to unsigned 32 integers (U32), just so I can pass the refnums between VI's easier.
Another VERY common typecast is if you want to display the ASCII value of a character. Run the string character "A" into a typecast, and set the output type as a Unsigned 8 bit number (U8), and you will see 0x41. Take a look at my example VI's to see what I mean.
David
Attachments:
Type_cast_Example5.vi ‏16 KB
Type_cast_Example6.vi ‏18 KB