As the name implies, this library was originally written to work with mmCIF files using C++ as programming language. The design of this library leans heavily on the structure of CIF files. These files can be thought of as a text dump of a relational databank with, often but not always, a very strict schema describing the data. These schema's are called dictionaries.

Using information from the content of a mmCIF file and an optional schema, libcifpp allows you to access the data in the file as a collection of datablock each containing a collection of categories with rows of data. The categories can be searched for data using queries written in regular C++ syntax. When a dictionary was specified, inserted data is checked for validity. Likewise removal of data may result in cascaded removal of linked data in other categories using parent/child relationship information.

Since there were still many programs using the legacy PDB format at the time development started, a layer was added that converts data to and from PDB format into mmCIF format. This means you can manipulate PDB files as if they were normal mmCIF files.

Apart from this basic functionality, libcifpp also offers code to help with symmetry calculations, 3d manipulations and obtaining information from the CCD Chemical Component Dictionary.