[LV 8.2.1] TDMS Get Property Bugs

[PJM_labview]

The attached VIs demonstrate 2 bugs with the TDMS Get Property primitive

1) Attempting to read properties that do not exist from a TDMS file return whatever was last read from the TDMS get property primitive (from whatever was the last TDMS file the TDMS get Property was invoked on). This is VERY confusing.

Severity: High

Work Around: Sort of one: Generate an explicit error with the property you are attempting to read prior you read them (see attached example).

2) Attempting to invoke TDMS get Property with a blank property name input on a TDMS file does crash LV

Severity: Medium

Work around: don't read blank property name

To see both these bug in action, extract the attached zip in a folder and run "demo bug.vi" and use the provided TDMS files "No Header Info.tdms" and "Has Header Info.tdms" in the TDMS file Path Controls

Note1: The "No Header Info.tdms" contains a sinusoid waveform

Note2: The "Has Header Info.tdms" contains a header with file type="Trace Data to TDMS" and file version="2.0"

http://forums.lavag.org/index.php?act=attach&type=post&id=5675

http://forums.lavag.org/index.php?act=attach&type=post&id=5677

http://forums.lavag.org/index.php?act=attach&type=post&id=5676

[Herbert]

QUOTE(PJM_labview @ Apr 30 2007, 08:21 PM)

1) Attempting to read properties that do not exist from a TDMS file return whatever was last read from the TDMS get property primitive (from whatever was the last TDMS file the TDMS get Property was invoked on). This is VERY confusing.

Yep, that's a known issue. The door on 8.2.1 closed too early to get the fix in.

http://forums.ni.com/ni/board/message?boar...uireLogin=False

QUOTE(PJM_labview @ Apr 30 2007, 08:21 PM)

2) Attempting to invoke

TDMS get Property

with a blank property name input on a TDMS file does crash

LV

Thanks for catching that. I had never seen that one. It seems to crash only if the output is a variant. CAR# 4909S6WJ.

Thanks,

Herbert

[PJM_labview]

QUOTE(Herbert @ May 1 2007, 09:00 AM)

Yep, that's a known issue. The door on 8.2.1 closed too early to get the fix in.

http://forums.ni.com/ni/board/message?boar...uireLogin=False

Thanks for pointing to that thread. Unfortunately the described workaround (Check the found output) does not work.

In the example I provided, If you probe the SubVI (Read Data Header from TDMS.vi) found output of the TDMS Get Property, you will see that it return True when reading a TDMS file with no header, meaning in return true when the property does not exist (See Below).

http://forums.lavag.org/index.php?act=attach&type=post&id=5687

QUOTE(Herbert @ May 1 2007, 09:00 AM)

...Thanks for catching that. I had never seen that one. It seems to crash only if the output is a variant. CAR# 4909S6WJ.

Thanks for the CAR.

PJM

[Herbert]

QUOTE(PJM_labview @ May 1 2007, 02:34 PM)

Unfortunately the described workaround (Check the found output) does not work.

PJM

I guess we'll have to get ugly then. "Get Properties" with no property name and no type wired to it will give you a list of all property names. Worst case that can be used to verify whether a property is there or not.

Herbert