As PMIx does not require that a particular environment (or even PMIx implementation) support all APIs and/or associated attributes, it can sometimes be difficult to determine the available support on a given system. This is particularly worrisome when porting applications and containers across environments, and users have requested that some API-based mechanism be made available for querying the local level of support.

The PMIx_Query API provides a mechanism for meeting this need. On systems that support it, applications can request a list of supported APIs and attributes for each API from the client PMIx library, the PMIx server, and the host environment.

More details to come.