\section{Runtime Compiler Functionality}
\label{sec:runtime-compiler-functionality}

The runtime compiler allows inclusion of double quoted (`` ``) 'C'
language style
functions within unformatted input files.  The functions are
evaluated during program setup or execution to calculate independent
solution variables. 

This provides the user with an endlessly flexible method for
describing boundary conditions, initial conditions, source terms,
material properties, or any other independent variable.

The specific variable names expected within runtime compiled functions
depends on the host code and the context of the function use. In
general it should be remembered that the runtime functions return
quantities by modifying variables that are passed in by reference.

%%% NOTE: the following file is copied directly from alegra/toolkit/rtcmopiler
\input{rtclang}
