Re: First stage of Quesa changes now complete

[James W. W. <ja...@wr...>]

At 1:23 PM +0000 1/24/05, Roger Holmes wrote:

>For my remaining 'slack' time I would like your opinions on the 
>possible use of C++ memory
>allocation and construction facilities. On Macintosh I think that 
>using statements like:
>
>  E3ClassInfo* theInfo = new E3ClassInfo ;
>
>E3ClassInfo* theClass = (E3ClassInfo*) Q3Memory_AllocateClear ( 
>sizeof ( E3ClassInfo ) ) ;
>
>are (except for the zeroing of the block of memory) equivalent as 
>they both end up calling
>malloc to actually reserve the memory. Am I correct, and what is the 
>situation on the other
>platforms?

When compiled with Q3_MEMORY_DEBUG, E3Memory_AllocateClear uses a 
block trailer to test for buffer overruns.  Exactly what operator new 
does on the Mac with CodeWarrior depends on whether we're talking CFM 
or Mach-O, and what options were used to compile the runtime library. 
The default on Mach-O is that operator new calls malloc.

Also bear in mind that E3ClassInfo* theInfo = new E3ClassInfo ; would 
throw an exception if the allocation fails, unless you write it as
E3ClassInfo* theInfo = new(std::nothrow) E3ClassInfo ;
-- 
   James W. Walker, ScriptPerfection Enterprises, Inc.
   <http://www.write-brain.com/>