Collective Calling Requirements
in Parallel HDF5 Applications

• HDF5 functions that must be called collectively and when in a parallel computing environment
• Properties that must be used in a coordinated manner in a parallel computing environment

The term Macro in the “Additional notes” column indicates that the first item in the “Function” column of the same row is a macro that is selectively mapped to one of the two immediately-following functions. For example, H5Acreate is a macro that can be mapped to either H5Acreate1 or H5Acreate2. This mapping is configurable and is explained in “API Compatibility Macros in HDF5.” The macro structure was introduced at HDF5 Release 1.8.0.

Function	All processes: same datatype & dataspace	All processes: same access properties	All processes: same creation properties	Available in releases since	Additional notes
H5Acreate H5Acreate1 H5Acreate2	✓	✓	✓	1.8.x	Macro The function H5Acreate was renamed to H5Acreate1 at Release 1.8.0.
H5Acreate_by_name	✓	✓	✓	1.8.x
H5Adelete
H5Adelete_by_idx				1.8.x
H5Adelete_by_name				1.8.x
H5Arename				1.6.x
H5Arename_by_name				1.8.x
H5Awrite					Because raw data for an attribute is cached locally, all processes must participate in order to guarantee that future H5Aread calls return correct results on all processes.
H5Dcreate H5Dcreate1 H5Dcreate2	✓	✓	✓	1.8.x	Macro The function H5Dcreate was renamed to H5Dcreate1 at Release 1.8.0.
H5Dcreate_anon	✓	✓	✓	1.8.x
H5Dextend					All processes must participate only if the number of chunks in the dataset actually changes. All processes must use the same dataspace dimensions.
H5Dset_extent				1.6.x	All processes must participate only if the number of chunks in the dataset actually changes. All processes must use the same dataspace dimensions.
H5Fclose					All processes must participate only if this is the last reference to the file identifier.
H5Fcreate		✓	✓
H5Fflush
H5Fmount
H5Fopen		✓
H5Freopen
H5Funmount
H5Gcreate H5Gcreate1 H5Gcreate2		✓	✓	1.8.x	Macro The function H5Gcreate was renamed to H5Gcreate1 at Release 1.8.0.
H5Gcreate_anon		✓	✓	1.8.x
H5Glink
H5Glink2				1.6.x
H5Gmove
H5Gmove2				1.6.x
H5Gset_comment
H5Gunlink
H5Idec_ref				1.6.x	This function may be called independently if the object identifier does not refer to an object that was collectively opened.
H5LIinc_ref				1.6.x	This function may be called independently if the object identifier does not refer to an object that was collectively opened.
H5Lcopy				1.8.x
H5Lcreate_external			✓	1.8.x
H5Lcreate_hard			✓	1.8.x
H5Lcreate_soft			✓	1.8.x
H5Lcreate_ud			✓	1.8.x
H5Ldelete				1.8.x
H5Ldelete_by_idx				1.8.x
H5Lmove				1.8.x
H5Ocopy				1.8.x
H5Odecr_refcount				1.8.x
H5Oincr_refcount				1.8.x
H5Olink				1.8.x
H5Oset_comment				1.8.x
H5Oset_comment_by_name				1.8.x
H5Rcreate
H5Tcommit H5Tcommit1 H5Tcommit2		✓	✓	1.8.x	Macro The function H5Tcommit was renamed to H5Tcommit1 at Release 1.8.0.
H5Tcommit_anon		✓	✓	1.8.x

Function	All processes: same datatype & dataspace	All processes: same access properties	All processes: same creation properties	Available in releases since	Additional notes
H5Aclose					All processes must participate only if all file identifiers for a file have been closed and this is the last outstanding object identifier.
H5Aopen		✓		1.8.x
H5Aopen_by_idx		✓		1.8.x
H5Aopen_by_name		✓		1.8.x
H5Aopen_idx		✓
H5Aopen_name		✓
H5Dclose					All processes must participate only if all file identifiers for a file have been closed and this is the last outstanding object identifier.
H5Dopen H5Dopen1 H5Dopen2		✓		1.8.x	Macro The function H5Dopen was renamed to H5Dopen1 at Release 1.8.0.
H5Gclose					All processes must participate only if all file identifiers for a file have been closed and this is the last outstanding object identifier.
H5Gopen H5Gopen1 H5Gopen2		✓		1.8.x	Macro The function H5Gopen was renamed to H5Gopen1 at Release 1.8.0.
H5Iget_file_id				1.8.x
H5Oclose				1.8.x	All processes must participate only if all file identifiers for a file have been closed and this is the last outstanding object identifier.
H5Oopen		✓		1.8.x
H5Oopen_by_addr		✓		1.8.x
H5Oopen_by_idx		✓		1.8.x
H5Rdereference
H5Tclose					All processes must participate only if the datatype is for a committed datatype, all the file identifiers for the file have been closed, and this is the last outstanding object identifier.
H5Topen H5Topen1 H5Topen2		✓		1.8.x	Macro The function H5Topen was renamed to H5Topen1 at Release 1.8.0.