>On 16 Apr 2002, at 11:15, Timothy Swenson wrote:
>> 1 - What is a Forced Free?
>> I know that you FREE a THING when an application stops using it, but I can't

>> find an explanation for FORCED FREE.
>
>Forced free is when the job owning the thing is removed. A thing 
>could be set up in such a way that the linkage block is not stored 
>in the common heap, but within the memory area of a job. When 
>that job disapperas, so will the thing. Hence a routine to make sure 
>that all other jobs using this thing will also disappear - that is 
>forced free.

This sounds a lot like a ZAP (removing the THING and all Jobs on it's USAGE
list).  Is there a situation when a Forced Free would apply versus a Zap?

>> 2 - What is a Forced Zap?
>> The TT docs talk about ZAP and use the term FORCED ZAP in defining the THING

>> table.  It looks like a FORCED ZAP is just another word for ZAP.  Is this
correct?
>
>Sorry, I wan't able to find where it mentiones a forced zap. A zap is 
>normally the removal of a thing. You can force remove a thing.

The online THING documentation mentionens "Forced Zap" but is changed in the
SMSQ/E docs to "thing owner is removed".  I should have caught this.


>> 3 - Pointer to "close" routine vs. Pointer to code
>> In the THING table, TH_FRFRE is defined as a Pointer to "close" routine for

>> Forced Free, and TH_FFREE is defined as a Pointer to code to Force Free a
THING.
>>  What's the difference between the "close" routine and code for Forced Free.

>>  Would these two pointers point to the same code or are they two unique pieces

>> of code that do two different operations?  To me it looks like the two pointers

>> are redudant.
>
>TH_FRFRE is an OS supplied piece of code - don't touch it. 
>TH_FREE is the code the thing writer supplies for a forced free (i.e. 
>the job ownning the thing is removed).

The statement in the SMSQ/E docs just above the definition of the THING table
states: "Items from TH_THING onwards (inclusive) must be filled in by the 
initialization
code..."

This leads me to the conclusion that the fields TH_NXTTH, TH_USAGE, TH_FRFRE,
TH_FRZAP are all filed in by the system and the user does not need to worry
about them.

Tim Swenson
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