Which is evaluated first: lock or precondition?

[tom_from_goodrich]

I am using the parallel model to support thermal cycle testing. At initialization I check the power supplies. The sequence to perform this check is locked, for one process at a time, and also has a precondition so that only the first thread will actually open the sequence. The precondition being checked is true at entry into the sequence and then false as a poscondition of the locked sequence.

If I check the precondition while the first thread is still in the sequence, it will evaluate to true but the sequence will be locked. If I don't check the precondition after the sequence is unlocked (the first thread finishes), then will I enter the sequence or will the precondition be checked again before entry?

[Nicks]

Hi Tom,
Lock is evaluated before precondition. Section 6 page 25-26 of the teststand user manual describes the sequence of events for a step to run.

Hope this helps,

Nick

[Scott_Richardson]

Tom -
The Table in TestStand 2.0/2.0.1 User Manual is incorrect. The table was corrected in the TestStand 2.0 Release Notes, but unfortunately the table was dropped from the TestStand 2.0.1 Release Notes.

To answer your question, the precondition is evaluated before the mutex is acquired.

The lock is acquired if the step is force to Pass, Fail or Skip though.

Scott Richardson (NI)