On Wed, Sep 20, 2023 at 04:46:12PM +0200, Thomas Haller wrote: > On Wed, 2023-09-20 at 16:05 +0200, Phil Sutter wrote: > > On Wed, Sep 20, 2023 at 03:13:39PM +0200, Thomas Haller wrote: > > > > > > + mp_get_memory_functions(NULL, NULL, &free_fcn); > > > > Do we have to expect the returned pointer to change at run-time? > > Because > > if not, couldn't one make free_fcn static and call > > mp_get_memory_functions() only if it's NULL? > > Hi Phil, > > > no, it's not expected to EVER change. Users must not change > mp_set_memory_functions() after any GMP objects were allocated, > otherwise there would be a mixup of allocators and crashes ahead. > > However, I didn't cache the value, because I don't want to use global > data without atomic compare-exchange (or thread-local). Doing it > without regard of thread-safety so would be a code smell (even if > probably not an issue in practice). And getting it with atomic/thread- > local would be cumbersome. It's hard to ensure a code base has no > threading issues, when having lots of places that "most likely are > 99.99% fine (but not 100%)". Hence, I want to avoid the global. OK, thanks. > I think the call to mp_get_memory_functions() should be cheap. Yes, the function is indeed very simple. Cheers, Phil
