Re: C++: operator new and disabled exceptions

[Christian BRUEL <christian dot bruel at st dot com>]

hello,

there is a difference between calling new and new (std::nothrow) from a 
fno-exceptions context:

- new (std::nothrow) would return 0 in case of error
- new () would throw std::bad_alloc that would finish in 
std::terminate() or abort()

so there is a possible difference in behavior if an -fno-exceptions 
application relies on std::terminate().

so if you patch gcc to use the nothrow internally, you would need to 
compile all your applications and all your libraries and runtimes with 
-fcheck-new.

Christian

Christophe LYON wrote:
> Hello,
>
> I have already asked this question on gcc-help (see 
> http://gcc.gnu.org/ml/gcc-help/2007-09/msg00328.html), but I would like 
>  advice from GCC developers.
>
> Basically, when I compile with -fno-exceptions, I wonder why the G++ 
> compiler still generates calls to the standard new operator (the one 
> that throws bad_alloc when it runs out of memory), rather than 
> new(nothrow) (_ZnwjRKSt9nothrow_t) ?
>
> In addition, do you think I can patch my GCC such that it calls 
> new(nothrow) when compiling with -fno-exceptions, or is it a bad idea? 
> (compatibility issues, ...)
>
> Thanks for your recommendation,
>
> Christophe.