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diff --git a/doxygen/dox/cookbook/Attributes.dox b/doxygen/dox/cookbook/Attributes.dox new file mode 100644 index 0000000..68fd159 --- /dev/null +++ b/doxygen/dox/cookbook/Attributes.dox @@ -0,0 +1,38 @@ +/** \page Attributes + +\section Attributes + +\subsection CB_LargeAttributes Creating "Large" HDF5 Attributes + +\par Problem +You would like to use HDF5 attributes the size of whose values +exceeds a few dozen kilobytes + +\par Solution +A file format change in the HDF5 1.8.x family of library releases made it +possible to have attributes larger than about 64 KiB. Ensure that the lower +library version bound for new HDF5 item creation is at least 1.8.x, and create +larger attributes as usual.\n +In the example below, we create an attribute whose value occupies 4 MiB. + +\note This feature is only supported in HDF5 1.8.x+ + +\snippet{lineno} Attributes.c large_attribute + +\par Discussion +Large attributes are supported only in HDF5 versions 1.8.x and higher. +This has implications for the accessibility of your HDF5 files and +is your call.\n +Since there are no size limitations for large attributes, it might +seem tempting to mistake them for dataset stand-ins. This is not the +case, for at least two reasons: +1. Attributes decorate HDF5 objects, have their own local namespace, + and can't be link targets. +2. Attribute I/O treats the attribute value as atomic, i.e., there + is no support for partial I/O. A large attribute will always be + read or written in its entirety. + +\par See Also +See \ref CB_MaintainCompat for HDF5 compatibility implications. + + */
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