The Esterel v5 21 System Manual - Courses

3.3. C CODE FOR DATA HANDLING 39
Remark: It is convenient to write the string conversion functions
together with the other data-handling functions. Their definitions
can be enclosed in a “#ifdef SIMUL” directive, making
them defined only in simulation mode.
3.3.5 Constants
Each constant used in the Esterel program must be defined in C with the
same name, unless it is initialized in the Esterel code. A constant can
be defined either by a #define directive in prog.h or by a standard C
variable definition. If not #defined, a constant is automatically declared to
be extern in prog.c. It can therefore be defined in any other file. Consider
the example:
constant NUMBER_OF_PERSONS: integer,
LUNCH_TIME: TIME;
Then prog.h can contain
#define NUMBER_OF_PERSONS 45
and prog data.c can contain:
TIME LUNCH_TIME = {12, 0, 0};
3.3.6 Functions
Each function used in the Esterel program must have a C definition. The
definition can be given either by a #define directive in prog.h or by a classical
C function definition. If not #defined, the C function is automatically
declared to be extern in the generated file prog.c.
A C function definition must match the source function type declaration.
For example, let us define the function declared in the PROG module by the
following Esterel declaration:
function FETCH (ARRAY_10_OF_TIME, integer) : TIME;
A possible definition is:
TIME FETCH (a, i)
ARRAY_10_OF_TIME a;
int i;
{
return(a.array[i]);
}