On 2/8/15 5:16 AM, John Colvin wrote:
On Sunday, 8 February 2015 at 12:43:38 UTC, FG wrote:
On 2015-02-08 at 03:19, Andrei Alexandrescu wrote:
Indeed we have no safe way to wrap free.
How about this to prevent double free:
Wrapped malloc keeps a static thread-local lookup structure for
successful allocations (if having to release memory from the same
thread is an acceptable requirement).
Wrapped free looks up the pointer in that lookup structure and, if
found, frees memory, removes the lookup entry and sets the argument of
the call to zero (if it was a pointer) or sets its length and ptr to
zero (if it was a dynamic array).
It's not completely safe, but for that GC would have to be used instead.
I don't have any data, but I'd image most double-frees come from
multiple references to the same data, not repeated calls to free on the
same reference.
I think the same. In C++ circles zeroing the pointer after freeing is
considering an antipattern - what with false sense of security etc. --
Andrei
