🚀 go-pugleaf

In article <839@rulcvx.LeidenUniv.nl> (W. Jaffe) writes:
>I have an interesting problem. I wonder if it has any value
>to check whether an AllocMem of 1Kb fails. 
>In my opinion it is an absolute waste of time and space to do
>such a check,  ...

Consider that doing such a check in assembly language is two
instructions (Test and branch) which takes very little time and
very little space.

>	       ,,, because the system would have crashed long before
>only 1Kb was left. Intuition don't like a low memory environment.

You have to think to yourself, "Is this a good thing?" (that Intuition
doesn't like low memory) And the other thing you have to think about
is "What if Intuition has already allocated all the memory it needs?"

You see the reason you ask these two questions is simple. In the first
case, it is clearly a bug that Intuition doesn't deal with low memory
conditions. Given that, you can presume that Commodore will eventually
fix it (possibly in 2.0 :-)). That would mean that now Intuition is
merely grinding along with 768 bytes free and the user is getting the
maximum possible use out of their system and suddenly _your_ program
crashes the system because it didn't check to see if it really got
the 1Kb it asked for. No don't you feel silly? And from the users
perspective it will sound like "Gee, this stupid programmer couldn't
spare 4 bytes and 11 machine cycles to see if is AllocMem() succeeded,
instead he crashes my system!" They are not going to like you my
friend. 

The second question deals more with the "rip-cord" effect of memory
management. One way of "fixing" intuitions problems will be to give
it its own memory pool to play with. That would mean the AllocMem
results might fail when Intuition had all of the memory it needed. 
Again, for a few cycles, and even fewer bytes you've screwed the
user by deciding not to check your results. 

>Also, it is absolute nonsense to check an OpenLibrary(graphics.library)
>call. If it is not there, you can better go to a repair shop.
>Of course, I like to know how others think about this subject.

Nonsense? Isn't that a fairly strong word? What about trying to open
Version 36 of the library and only version 34 is present? Eh? What
happens when someone substitutes a disk based graphics.library
on their system which has a custom video display system and you
can't load it into memory ? Again, 4 bytes and 11 cycles. That's
all we ask. 

When you hold these opinions you need to ask yourself, "Why would
this occur, and if I ignore it what are the consequences?" Well
on the Amiga the "Why" portion varies but the consequences are
usually fatal. I would ask you "Why not?" it is easy to check
these things and it makes your software much more reliable. Your
reasons above don't outweigh the question of reliability.


--
--Chuck McManis						    Sun Microsystems
uucp: {anywhere}!sun!cmcmanis   BIX: <none>   Internet: cmcmanis@Eng.Sun.COM
These opinions are my own and no one elses, but you knew that didn't you.
"I tell you this parrot is bleeding deceased!"