On 23 mei 2005, at 02:29, Konstantin Münning wrote:
What would you suggest to return under an OS like Windows, Mac OS X
or
Linux? The current "free" memory of the OS? Free memory + buffer
cache
- minimal buffer cache size enforced by the OS? The previous +
available swap space - "wired" (i.e., not swappable to disk) memory?
Just a constant? Something different possibly?
I have written in my previous mail(s) that I think the best return
value
would be the biggest value with which a getmem would be successful if
memory conditions haven't changed inbetween.
The only way to know that is to perform getmem's with every increasing
values until one fails.
Most programs work most of the time except under heavy load. That's not
a good argument.
I beg you pardon? I think the argument that most programs do not work
well under heavy load is an extremely bad argument to encourage even
more buggy programming.
Please let it be the programmers choice
what to do and how to handle this.
Only using tools that make sense, everything else would be snake oil
(and in reality nothing would be handled).
A compiler should be providing the
means, not taking them away.
It should not provide known defunct means.
Anybody writing a program knows that there
may be flaws.
No, if you use RTL routines, you expect them to work.
A warning (with an advice how to make it better) should
still be the best for this.
People don't read the manual.
{$ifdef HASGETHEAPSTATUS}
status:=GetFPCHeapStatus;
startmem:=status.CurrHeapUsed;
{$else HASGETHEAPSTATUS}
startmem:=memavail;
{$endif HASGETHEAPSTATUS}
I'm not sure if I understand it right as GetHeapStatus is not
documented
well (I've found no reference for the meaning of the fields of the
returned record) but it seems that someone repaced here memavail with
another code which does about the same and has therefore the same flaw.
The above code is not used to check whether there's still enough free
memory left, it's only used to calculate how much memory is used by the
compiler.
I would hapily contribute the code for a better MemAvail/MaxAvail
function if that's the problem. I would like to be able to use the
latest compiler which now I definitely can't as I must have the BP7
compatibility which is very good in 1.0.10.
You can make a unit which contains a dummy memavail and maxavail which
always return a value of 1GB or so, then your program will also always
work except under heavy load (if that is really what you want). There's
no use in investing lots of time in making very complex routines to
query all sorts of information from the OS and then have it fail in
exactly the same circumstances as when you return a plain constant.
Jonas
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