MPIGETADDRESSLOC

MPIGETADDRESSLOC is an internal helper used in some MPI implementations to determine the memory address location of a given object for the purposes of the MPI datatype engine and address translation. It is not part of the MPI standard and its exact form can vary between implementations and versions.

The main purpose of MPIGETADDRESSLOC is to provide a portable means of converting a host pointer into a location value that can be used by MPI’s internal machinery when constructing and packing derived datatypes, as well as when supporting address-related operations such as MPI_Get_address. By computing a consistent offset or location, the MPI library can manage displacements, alignments, and memory layouts across different architectures and languages.

In practice, MPIGETADDRESSLOC may be implemented as a macro or an inline function that uses pointer arithmetic to yield an MPI_Aint-like value representing the address location relative to a base or reference object. The exact signature is implementation-specific, but the goal is to produce a stable, integer address representation that can be used within the internal datatype description and communication code.

Usage and relevance are primarily internal to the MPI library itself. Applications typically do not call MPIGETADDRESSLOC directly; instead, they rely on standard interfaces such as MPI_Get_address for obtaining pointer locations and on the library’s datatype constructors for building complex data layouts.

See also: MPI_Get_address, MPI_Aint, derived datatypes, MPICH and related MPI implementations.