HDF5 NeXus writer API Reference

The following functions are part of the HDF5 NeXus writer API version 1.0.

Programming Hints:

To use any of these functions or subroutines, you must first include the relevant include file in your application.

The following line includes the HDF5 NeXus writer API package, H5NX, in C++ applications:
#include "h5nx.hpp"

The C++ Interfaces:

Initialization functions Dataset functions Group, link, attribute functions Performance functions
Name: H5nx
Signature:
H5nx ()
Purpose:
Creates a H5nx instance.
Description:
H5nx is the class constructor and creates an instance of the class. It takes no arguments and initializes private class variables.
Parameters:
Returns:
No return value.
Name: H5NXcreate_file
Signature:
int H5NXcreate_file ( const std::string& file_name )
Purpose:
Creates a NeXus file.
Description:
H5NXcreate_file creates a HDF5 file named file_name and writes NeXus metadata to it, namely root group attributes conforming to the NeXus format specification.
Parameters:
Returns:
Returns a non-negative value if successful; otherwise returns a negative value.
Name: H5NXclose_file
Signature:
int H5NXclose_file ()
Purpose:
Closes the NeXus file.
Description:
H5NXclose_file closes the HDF5 file created with H5NXcreate_file.
Parameters:
Returns:
Returns a non-negative value if successful; otherwise returns a negative value.
Name: H5NXmake_dataset_string
Signature:
int H5NXmake_dataset_string ( const std::string& group_path, const std::string& dataset_name, const std::string& data )
Purpose:
Creates and writes a string dataset.
Description:
H5NXmake_dataset_string creates a dataset named dataset_name in the path group_path, and writes the string data to it.
Parameters:
Returns:
Returns a non-negative value if successful; otherwise returns a negative value.
Name: H5NXmake_dataset_scalar
Signature:
template < typename NumT > int H5NXmake_dataset_scalar ( const std::string& group_path, const std::string& dataset_name, const NumT& value )
Purpose:
Creates and writes a scalar numerical dataset.
Description:
H5NXmake_dataset_scalar creates a dataset named dataset_name in the path group_path, and writes the scalar value value to it.
Parameters:
Returns:
Returns a non-negative value if successful; otherwise returns a negative value.
Name: H5NXmake_dataset_vector
Signature:
template < typename NumT > int H5NXmake_dataset_vector ( const std::string& group_path, const std::string& dataset_name, const std::vector< NumT >& vec, const std::vector< hsize_t >& dim_vec )
Purpose:
Creates and writes a vector numerical dataset.
Description:
H5NXmake_dataset_vector creates a dataset named dataset_name in the path group_path, and writes the vector vec to it.
Parameters:
Returns:
Returns a non-negative value if successful; otherwise returns a negative value.
Name: H5NXcreate_dataset_extend
Signature:
int H5NXcreate_dataset_extend ( const std::string& group_path, const std::string& dataset_name, int nxdatatype, hsize_t chunk_size )
Purpose:
Creates an extendable dataset.
Description:
H5NXcreate_dataset_extend creates a dataset named dataset_name in the path group_path.
Parameters:
Returns:
Returns a non-negative value if successful; otherwise returns a negative value.
Name: H5NXappend_slab
Signature:
template < typename NumT > int H5NXappend_slab ( const std::string& dataset_path, const std::vector< NumT >& vec )
Purpose:
Appends a vector to a dataset.
Description:
H5NXappend_slab appends a vector vec to the dataset dataset_path.
Parameters:
Returns:
Returns a non-negative value if successful; otherwise returns a negative value.
Name: H5NXmake_group
Signature:
int H5NXmake_group ( const std::string& group_path, const std::string& class_name )
Purpose:
Creates a group.
Description:
H5NXmake_group creates a group named group_path with the NeXus class class_name.
Parameters:
Returns:
Returns a non-negative value if successful; otherwise returns a negative value.
Name: H5NXmake_link
Signature:
int H5NXmake_link ( const std::string& current_name, const std::string& destination_name )
Purpose:
Creates a HDF5 link.
Description:
H5NXmake_link creates a link named destination_name from an existing name current_name.
Parameters:
Returns:
Returns a non-negative value if successful; otherwise returns a negative value.
Name: H5NXmake_attribute_string
Signature:
int H5NXmake_attribute_string ( const std::string& dataset_path, const std::string& attr_name, const std::string& attr_value )
Purpose:
Creates and writes a string attribute.
Description:
H5NXmake_attribute_string creates an attribute named attr_name in the dataset named dataset_path and writes the string attr_value to it.
Parameters:
Returns:
Returns a non-negative value if successful; otherwise returns a negative value.
Name: H5NXmake_attribute_scalar
Signature:
template < typename NumT > int H5NXmake_attribute_scalar ( const std::string& dataset_path, const std::string& attr_name, const NumT& value )
Purpose:
Creates and writes a scalar numerical attribute.
Description:
H5NXmake_attribute_scalar creates an attribute named attr_name in the dataset named dataset_path, and writes the scalar value value to it.
Parameters:
Returns:
Returns a non-negative value if successful; otherwise returns a negative value.
Name: H5NXflush
Signature:
int H5NXflush ()
Purpose:
Writes data to disk.
Description:
H5NXflush causes all buffers associated with a file to be immediately flushed to disk.
Parameters:
Returns:
Returns a non-negative value if successful; otherwise returns a negative value.
Name: H5NXset_cache_size
Signature:
void H5NXset_cache_size ( size_t size )
Purpose:
Set the chunk cache size.
Description:
H5NXset_cache_size sets the chunk cache size to size.
Parameters:
Returns:
Nothing.


H5NX is used at the Spallation Neutron Source of the Oak Ridge National Laboratory