Re: [Boost-users] [bind] using NULL as a bound argument

On Mon, Jun 16, 2008 at 01:01:58PM +0200, Ovanes Markarian wrote:

On Mon, Jun 16, 2008 at 10:45 AM, Marc Horowitz wrote:

...

"Ovanes Markarian" writes:

...

...

in this case template deduction does not work (or works a bit different as assumed).

This one should work: (std::tr1::bind(f, _1))(static_cast(NULL));

This is static type safety of C++. The next standard will introduce null_ptr. If used as you suggested, then nothing prevents this BAD code to

Right, null_ptr will be part of C++. Nevertheless NULL was never part of C++! g++ defines it for convenience, the Intel compiler does not. It is often defined by 3rd libraries. glib uses: #ifndef NULL # ifdef __cplusplus # define NULL (0L) # else /* !__cplusplus */ # define NULL ((void*) 0) # endif /* !__cplusplus */ #endif /usr/include/linux/stddef.h is similar but uses 0 instead of 0L in C++ mode. Nevertheless even with nullptr as defined as in http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2004/n1601.pdf I wasn't able to let the Intel compiler warning warning #1881: argument must be a constant null pointer value vanish. The code I used is: XtVaCreateManagedWidget("widget_name", xmFrameWidgetClass, form, NULL); (where I replaced NULL by nullptr, ...) So don't rely on NULL. It's evil ... null_ptr doesn't help in all cases as well :-) Jens