[PROTON-985] Modify pn_transport_tick to explicitly use a monotonic clock, not wall clock time

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: proton-0.10
• Fix Version/s: proton-c-0.27.0
• Component/s: proton-c
• Assignee: Alan Conway
• Reporter: Ken Giusti
• Created: 18/Aug/15 13:19
• Updated: 10/Apr/19 08:50
• Resolved: 09/Feb/19 14:55

Description

The timestamp argument to pn_transport_tick is a pn_timestamp_t. pn_timestamp_t implies real time (wall clock) in that it's expressed as a time value based on epoch.

As seen in QPID-6698, using a real time value for that argument can lead to problems if the real time is adjusted (eg. timezone, daylight savings, drift).

Instead, pn_transport_tick should be passed a monotonic clock source - one that does not reflect changes in real time.

All documentation and examples should be updated accordingly.

Issue Links

• is depended upon by: PROTON-2030 Use CLOCK_MONOTONIC in proactors for pn_transport_tick
• is related to: DISPATCH-1270 Inapropriate use of CLOCK_REALTIME for periodic timer