Flag that indicates source of execution for Simulink block initialization code

Is there a recommended way to tell within Simulink block initialization code, whether it is being executed during a Simulink Coder build, or a simulation, or simply by copying the block? For example, I would like the block initialization code to interrupt a build if an error condition arises during a build (by throwing an exception), but I would like to have it work differently when the initialization code is executed simply as a result of placing the block in the model. Likewise, I would like the code to interrupt a simulation if the initialization code is executed as a result of simulation.