Re: question about nullptr

Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:

Tim Rentsch <tr.17687@z991.linuxsc.com> writes:
>

Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:
>

Tim Rentsch <tr.17687@z991.linuxsc.com> writes:
[...]
>

This posting has inspired me to try using (long)0.0
whenever a null pointer constant is needed.  As for
example
>
    (void*){ (long)0.0 }
>
as an argument to a variadic function where a pointer
is expected.

>
But surely ((void*)('/'/'/'-'/'/'/')) is more elegant.

>
Surely not.  Furthermore the form I showed has a point,
whereas this example is roughly the equivalent of a
first grade knock-knock joke.

>
I was of course joking.  I assumed you were as well.
>
What is the point of (void*){ (long)0.0 }?  I don't believe it's a
null pointer constant even in C23.

The null pointer constant is (long)0.0, which it must be for the
compound literal to work.  Besides making it obvious that (long)0.0
is a null pointer constant, the compound literal is safer than
using just a cast.

My example is.

Your example actually has two null pointer constants:  the
expression being casted, and the full expression casting a null
pointer constant to (void*).  But in neither case is that especially
obvious.  Also the expression you wrote is less safe.  For example,
if it had been written ((void*)('/'/'/'+'/'/'/')), the result would
still be legal C, and compile without problem, but would very likely
not be what was desired.  By contrast, if the compound literal had
been written (void*){ (long)1.0 }, it simply would not give a clean
compile, indicating that something is likely askew.