[ECOS] Question about "new" operator in C++ and "malloc()" function in C. Thanks a lot

[Jonathan Larmour]

Eric Donnat wrote:
> On 30 Jul 2003 11:43:53 +0100 Nick Garnett <nickg@ecoscentric.com>
> wrote:
>> We currently don't support any of the C++ runtime library routines.
>> To do this properly would also need a reorganization of the C library
>> to abstract out common code and preserve the expected relationships 
>> between functions.

I guess you are alluding to the I/O synchronisation requirements. Yes,
that used to be true, but libstdc++ is now based on top of stdio and
synchronises itself with that. This can sometimes be overkill and so
there's a libstdc++ function to disable that.

> You then may find some tricky things such as the basic
> 
> void *operator new(size_t size) { return my_alloc(size);}
> 
> is INVALID in C++ because returning a null pointer is UNSPECIFIED in
> the scope of the new operator. So you just can't say the problem is 'AS
> IS'. Mostly a working C++ new needs some support for exceptions,
> set_new_handler, unexpected exception handling, abnormal termination,
> set_terminate and the likes.
> 
> While supc++.a that comes when you are compiling GCC, probably handle
> much of such annoyances (Yes, I'm a C coder), I presume eCos is still
> laking from a review of the supc++.a code in order to get the whole
> stuff working, with fully analysed requirements (in CDL ??), with any
> weird code, and why not configurability (for ISO C++ sub-standard).

I suppose I'll say as usual that I've got exceptions working here (or used 
to anyway ;-)... old code base), but a final effort is needed to clean it 
up and contribute it, but enough of an effort that it probably ain't gonna 
happen till someone asks for it.

> IMHO, this is a full C++ guru job (I'm not the right guy for that,
> sorry). Even decoding the C++ standard is already a full daunting job.

I think there has to be a certain amount of emphasis on running 
libstdc++'s own tests rather than trying to guess whether it's implemented 
right or testing yourself.

Jifl
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