Public API

The public API of the H3 Core Library is defined in the file h3api.h.

API Versioning

The functions defined in h3api.h adhere to Semantic Versioning.

Header preprocessing

The file h3api.h.in is preprocessed into the file h3api.h as part of H3's build process. The preprocessing inserts the correct values for the H3_VERSION_MAJOR, H3_VERSION_MINOR, and H3_VERSION_PATCH macros.

API preconditions

The H3 API expects valid input. Behavior of the library may be undefined when given invalid input. Indexes should be validated with isValidCell or isValidDirectedEdge as appropriate.

The library attempts to validate inputs and return useful error codes if input is invalid. Which inputs are validated, and how precisely they are validated, may change between versions of the library. As a result the specific error code returned may change.

Function renaming

The H3_PREFIX exists to rename all functions in the H3 public API with a prefix chosen at compile time. The default is to have no prefix. This can be needed when linking multiple copies of the H3 library in order to avoid naming collisions. Internal functions and symbols are not renamed.