Constant values need to be defined

[rhc54]

Overview

The Standard currently only defines the name of PMIx constants - it does not assign them a value, thus leaving the value to each implementation. This creates a problem for vendors seeking to distribute implementation-agnostic products as they cannot know the meaning of a particular value returned by a function call.

Motivation

Implementation-agnostic products (e.g., debuggers) are typically compiled against one implementation, but are designed to work against whatever implementation is installed on the target system. This is done by using the combination of dlopen and dlsym to load the library and access its public APIs.

Unfortunately, the value of the constants in the code is determined at compile time - it isn't possible to load them via dlopen. Thus, the resulting binary is "locked" to the implementation against which it was compiled, thereby forcing the vendor to distribute implementation-specific copies of their product.

Discussion Items

The solution to the problem is to have the Standard define the actual value of each constant and not just its name. Doing this forces all implementations to use the same value, thus allowing for implementation-agnostic products to be distributed.