Am 12.10.2016 um 01:59 schrieb Stefan Beller:
+void git_attr_check_initl(struct git_attr_check **check_,
+ const char *one, ...)
{
- struct git_attr_check *check;
int cnt;
va_list params;
const char *param;
+ struct git_attr_check *check;
+
+ if (*check_)
+ return;
+
+ attr_lock();
+ if (*check_) {
+ attr_unlock();
+ return;
+ }
...
check = xcalloc(1,
- sizeof(*check) + cnt * sizeof(*(check->check)));
+ sizeof(*check) + cnt * sizeof(*(check->attr)));
...
+ *check_ = check;
+ attr_unlock();
Sigh. DCLP, the Double Checked Locking Pattern. These days, it should be
common knowledge among professionals that this naïve version
_does_not_work_ [1]!
I suggest you go without it, then measure, and only *then* optimize if
it is a bottleneck. Did I read "we do not expect much contention" somewhere?
[1] http://www.aristeia.com/Papers/DDJ_Jul_Aug_2004_revised.pdf C++
centric, but applies to C just as well
-- Hannes
