Answered Valid Stream

[whwar9739]

Good afternoon fellow Progress Programmers:

I have stumbled in to a situation where I would like to check the status of or validity of a defined stream. There are cases where the stream is getting used but has already been closed. Basically I would like to do something similar to VALID-HANDLE() but for a stream.

Thanks everyone.

 

[TomBascom]

That is to make sure that the trigger code you provide doesn't get changed by someone else.

You would enable this if your trigger Does Something Very Important That Ought Not Be Messed With. If your triggers are of no special consequence (like those in sports2000) then you would not take such steps.

 

[whwar9739]

That is to make sure that the trigger code you provide doesn't get changed by someone else.

You would enable this if your trigger Does Something Very Important That Ought Not Be Messed With. If your triggers are of no special consequence (like those in sports2000) then you would not take such steps.

Tom I think you meant to post this in a different thread.

 

[TomBascom]

Oops!

The answer to your stream question is "sorrry, no such method".

 

[RealHeavyDude]

You could get the handle to the stream and set the private-data attribute on the handle yourself everytime you open or close the stream accordingly. At least that's what I came up with some time ago. It's neither nice nor elegant but I didn't find any other way:

assign myHandle = stream myStream:handle.
/* Some stuff */
output stream myStream to value ( myFile ).
assign myHandle:private-data = 'open'.
/* Some stuff */
output stream myStream close.
assign myHandle:private-data = 'close'.

Coded in Internet Explorer 9 IDE - therefore no syntax check but you should get the idea.

Heavy Regards, RealHeavyDude.

 

[KrisM]

Question is, do you have access to make changes to the source code where this stream is opened and closed ?

 

[TomBascom]

My approach is - if in doubt, close it and re-open it.

 

[TheMadDBA]

Use SEEK(MySteam). It will return ? for closed streams, otherwise you get the current position in the file/stream.

 

[whwar9739]

Thanks RealHeavyDude! I had thought about that.
Yes KrisM I do have access to change the source code.
TheMadDBA, that sounds about perfect for what I need. I'll give it a try.

 

[TomBascom]

I like that seek( myStream ) trick! That could come in handy

 

[RealHeavyDude]

The seek ( ) is the much smarter solution. Didn't use it yet once in my ABL ( 4GL ) life though.

Heavy Regards, RealHeavyDude.

 

[Cecil]

I thought using the seek method has always been the standard method to test if a steam was open or closed. It was one of the first tips I learnt when developing printed reports to a serial dot-matrix printer on SCO UNIX on Progress V6.

I wish I could get my hands on those black glossy manuals because I sure it's documented in one of them as an example.

 

[Rob Fitzpatrick]

I wish I could get my hands on those black glossy manuals because I sure it's documented in one of them as an example.

I think I have the black manuals buried in my office somewhere...