H5Tconvert

herr_t H5Tconvert(hid_t src_id,  hid_t dst_id,  size_t nelmts,
       void *  buf,  void *  background,  hid_t plist_id)

Converts data from one datatype to another.

`src_id`	Source datatype identifier
`dst_id`	Destination datatype identifier
`nelmts`	Number of elements to convert
`buf`	Buffer containing data to convert (modified in place)
`background`	Background buffer, or null
`plist_id`	Dataset transfer property list identifier, or H5P_DEFAULT

Non-negative on success, negative on failure.