From:	"Rafał Maj" <r_maj AT poczta DOT onet DOT pl>
Newsgroups:	comp.os.msdos.djgpp
Subject:	memory reserve !!!!!!!!!!!!!!!!!!!!
Date:	Wed, 23 Aug 2000 16:32:47 +0200
Organization:	Academic Computer Center CYFRONET AGH
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To:	djgpp AT delorie DOT com
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Reply-To:	djgpp AT delorie DOT com

Hi,

In my program I allocate all memory like this :

    MyClass *ptr;
    try { ptr = new MyClass( var1, var2); }
    catch (std::bad_alloc) { cMemoryManager->needed( sizeof(MyClass) ); }
    // thanks to drew AT Poohstick DOT ORG

where cMemoryManager->needed(long SIZE) is function, with unloads SIZE bytes
of data from memory.

So now everything is fine - when program runs out of virtual memory, it
automaticly unloads unnessesary data.

BUT : some other functions (for example from libraries) are still allocating
memory in old way - just using  new. So when out-of-memory-error wil occur
in library function (and not in my program) then ofcourse my
cMemoryManager->needed function won't be called and program will crash.

===========================
So I want  new() operator to throw exceptions, not only when all memory is
used, but
when free memory is less then, for example 32Kb.
HOW CAN I DO THIS ???

1) I can't use any function like _go32_dpmi_get_free_memory... because they
don't show real amount of free memory.
2)This solution :
  try { some_library_fun(); }
  catch (std::bad_alloc) { cMemoryManager->needed( 64*1024 ); }
Isn't good because it's very *not* nice & It don't help if library function
uses malloc()

==============================
3) This solution will probably work but I think it is not nice... what You
think ?

    try { ptr = new MyClass( var1, var2); }
    catch (std::bad_alloc) { cMemoryManager->needed( sizeof(MyClass) ); }
    try { *TEST = new char[reserve_size]; }
    catch (std::bad_alloc) { cMemoryManager->needed(reserve_size); }
    delete TEST;

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