Should local pv has an initial value of zero?

[xihui]

Currently, the default value of a local pv is null if the initial value is not given. This results in some problems:

1. BOY doesn't know how to handle a connected pv with null value. What should it show to user? Another type of border? Will this expose unnecessary complexity to user?
2. Users need to add initial value to all local PVs even in most cases they don't care about the initial value, which add uncessary burden to user.

In BOY, I want to make things clear and easy to user: Disconnected means no value, Connected means it received new value. I don't want to expose extra states such as connected but has no value to user, because I think it means nothing to user.

So I would like to ask your opinion on this issue and please give a vote on it: should a local pv has an initial value of 0.0 or null?

Thanks,
Xihui

Proposed change to specification:

local pv has an initial value of 0.0

[gcarcassi]

-1 from me.

It does not cover all the previous use cases that I presented before.

[berryma4]

There is the issue that 0 is value that has meaning. So, if I have a service that hasn't returned a value yet, I would want it to be displayed null, because zero would be misleading.

As stated by Kay in cs-studio-core mail list (subject: "local pv initialization specification"):
"There has already been an opportunity to discuss this, a decision has been made.
In this month's CSS hangout, the majority of those present agreed that local variables must be initialized, and those initializers must all specify the same value.
If not initialized, you get null values. If trying to re-initialize with a different value, you get an exception."

Tagging with "wontfix", and we will close the issue unless there is new input to the conversation.