A Roadmap for the GraphBLAS C++ API

The GraphBLAS are building blocks for expressing graph algorithms in terms of linear algebra. Currently, the GraphBLAS are defined as a C API. Implementations of the GraphBLAS have exposed limitations in expressiveness and performance due to limitations in C. A move to $\mathrm {C}++$ should address many of these limitations while providing a simpler API. Furthermore, for methods based on user-defined types and operators, the performance should be significantly better. $\mathrm {C}++$ has grown into a pervasive programming language across many domains. We see a compelling argument to define a GraphBLAS $\mathrm {C}++$ API. This paper presents our roadmap for the development of a GraphBLAS $\mathrm {C}++$ API. Open issues are highlighted with the goal of fostering discussion and generating feedback within the GraphBLAS user community to guide us as we develop the GraphBLAS $\mathrm {C}++$ API.