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Diffstat (limited to 'doc/vfd-swmr-user-guide.md')
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diff --git a/doc/vfd-swmr-user-guide.md b/doc/vfd-swmr-user-guide.md index 650d869..cfb6848 100644 --- a/doc/vfd-swmr-user-guide.md +++ b/doc/vfd-swmr-user-guide.md @@ -447,6 +447,26 @@ problem. There is no schedule for those improvements. Improvements to VFD SWMR may also alleviate the problem. +## Iteration + +An application that reads in VFD SWMR mode should take care to avoid +HDF5 iteration APIs, especially when iterating large numbers of objects +or using long-running application callbacks. While the library is in an +iteration routine, it cannot track changes made by the writer. If the +library spends more than `max_lag` ticks in the routine, then its view +of the HDF5 file will become stale. Under those circumstances, HDF5 +content could be mis-read, or the library could crash with a diagnostic +assertion. + +## Object handles + +At the present level of development, the writer cannot invalidate +a reader's HDF5 object handles (`hid_t`s). If a reader holds an +object open---that is, it has a valid handle (`hid_t`) for the +object---while the writer deletes it, then reading content through +the handle may yield corrupted data or the data from some other +object, or the library may crash. + ## Microsoft Windows VFD SWMR is not officially supported on Microsoft Windows at this time. The |