Introduction 1
Introduction
The main requirements for the design of the C++ interface are:
• to provide the functionality of the C interface;
• to provide type safety by eliminating all use of void* pointers; and
• to provide an interface that is simpler to use than the C interface.
Some of the features of the C++ interface are:
• No IDs needed for netCDF’s variables, dimensions, or attributes.
• No explicit open or close calls needed for netCDF files; a constructor opens and a
destructor closes a file.
• No need to spec ify types for creating attributes; they will have the type of the value
provided.
• No use of void*: values are type-checked.
• Less indirection is needed for dimensions & dimension sizes than with the C interface.
A variable’s dimensions can be provided as arguments when defining a variable.
• Code for data types is isolated to make the addition of new types easier.
• No explicit ncredef or ncendef calls are needed for switching between define and data
modes. Whenever a mode switch is required, it happens implicitly.
The header file ‘netcdfcpp.h’ must be included in source code files using this interface.
This release provides the functionality of netCDF version 3.6.1.
This manual as sumes familiarity with Chapters 1 through 4 of the netCDF User’s Guide,
where the concepts of netCDF dimensions, variables, and attributes are discussed.
Class Hierarchy
The class for netCDF file objects is NcFile.
The components of a netCDF file are dimensions, variables, and attributes. There
is a class for each of these kinds of objects; NcDim, NcVar, and NcAtt. Variables and
attributes share some common characteristics that are factored out in the abstract base
class NcTypedComponent.
An auxiliary class, NcValues, provides a type for arrays of values that are read from
or written to netCDF files. Another auxiliary class, NcError, provides flexible facilities for
handling errors.
