Re: Joy of this, Joy of that

Lawrence D'Oliveiro <ldo@nz.invalid> writes:

On Sat, 23 Nov 2024 07:09:06 GMT, Charlie Gibbs wrote:

So it's the good old-fashioned way - free
each allocation one by one and hope you don't forget one.

>
One thing that helps is that free(3) is idempotent:

It is not. Freeing the same non-null pointer twice is a bug (and a
common source of vulnerabilities).

calling it on a NULL pointer is a harmless no-op, so there is no need
to check for NULL before calling it. So my standard technique
(simplifying somewhat) is

‘free() and null out all copies of the pointer that can ever reach
free() in the future’ is idempotent, if you can get it right (which is
usually not too hard in a well-organized program).

--
https://www.greenend.org.uk/rjk/