get number SYS$QIO calls for channel

[Alex Chupahin]

Hello all,
I do some number of
SYS$QIO(......)
without waiting for complete.

Can I get a number of noncompleted QIO somehere in program when needed?

[Volker Halle · Accepted solution]

Alex,

no. Not from the program itself. You need to do your own counting of the outstanding QIOs.

You could possibly see them with SDA> SHOW DEVICE x (if your QIOs are still outstanding on that device) or indirectly via SDA> SHOW PROC as a difference between either Buffered (or Direct) I/O count/limit.

Volker.

[Alex Chupahin]

ok, thank you

[abrsvc]

Couldn't you use the $GETJPI service to get the BIOLM and DIOLM values and calculate the outstanding IOs? I realize that this will take some coding, but that would essentially be the same as using SDA correct?

Dan

[John Gillings]

Alex,

> I do some number of
>SYS$QIO(......)
>without waiting for complete.

Hang on! You MUST be issuing each $QIO with an unique IOSB and buffer, yes? (This is NOT negotiable, if they're not unique, your I/Os WILL break).

Since you therefore have to manage the allocation and deallocation of IOSBs and buffers, there's a place in your code to count and keep track of outstanding buffers, which is the same as tracking outstanding $QIOs.

[Robert Gezelter]

Alex,

I agree with John. Each simultaneous IO needs an individual IOSB. It is a straightforward matter to make the IOSB part of a larger structure that in turn is counted (or part of a chain).

Checking quotas is not reliable, as they are process-wide and may reflect other operations that are independent of your code.

- Bob Gezelter, http://www.rlgsc.com

[twhjr]

Greetings,

What kind of device are you writting to?

I seem to remember long ago I wrote a quick little program to check mailbox queues.

Have Fun,
twhjr