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Section: 30.11.2 [time.zone.db] Status: New Submitter: S. B. Tam Opened: 2025-01-16 Last modified: 2025-02-07
Priority: 3
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Discussion:
N5001 30.11.2.2 [time.zone.db.list] p3:
Synchronization: This operation is thread-safe with respect to
reload_tzdb().
N5001 30.11.2.3 [time.zone.db.access] p2:
Synchronization: It is safe to call this function from multiple threads at one time.
N5001 30.11.2.4 [time.zone.db.remote] p3:
Synchronization: This function is thread-safe with respect to
get_tzdb_list().front()andget_tzdb_list().erase_after().
The standard does not define what "thread-safe" means, which makes the meaning of these sentences unclear. Does it mean that "concurrent calls do not introduce data races", or does it additionally require a single total order on these operations? In either case, it should be specified clearly.
[2025-02-07; Reflector poll]
Set priority to 3 after reflector poll.
"We're missing a guarantee that reload_tzdb() strongly happens before
a call to get_tzdb_list().front() that retrieves a newly added element.
Otherwise accessing any time_zone obtained from get_tzdb_list().front()
could race with the call to reload_tzdb() that writes the front of the list."
Proposed resolution: