The Esterel v5 21 System Manual - Courses

Chapter 3
The Esterel to C Interface
3.1 Introduction
The Esterel v5 system generates a C code file from a source Esterel program.
The C code can be generated either for direct execution, which is the default,
or for interactive simulation if Esterel is called with the -simul option.
The main object in the generated code is the reaction function, which
inherits the name of the compiled Esterel module. Inputs and outputs are
performed using auxiliary input and output functions whose names are automatically
computed from the module and signal names. The run-time
interface is purely procedural. No assumption is made on the operating
system that supports the execution. The decisions of when an input event
occurs and when signals should be considered as simultaneous are left to
the user. This makes it possible to execute the generated code in arbitrary
execution environments.
The run-time interface is independent on the code generation style: the
sorted equation code generated by the default option or by the -causal
option, the unsorted equation code generated by the -I option, and the
automaton code generated by the -A, -v3, and -S options have exactly the
same interface.
The generated C code may require some auxiliary code to define the
types, constants, functions, procedures, and tasks used in the module’s body.
This auxiliary code is called the data-handling code. Some master code is
also needed to realize the execution interface with the outside world, i.e.
detect input events, call the reaction function, and perform output actions.
We start in Section 3.2 by an overview of the data handling and execution
interface. In Section 3.3, we present the details of the data-handling
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