9.2 Function Names
The rules for function naming and function-argument naming are the same as for other variables; see the section on variables for more information on valid identifiers. For example,
real foo(real mu, real sigma);
declares a function named
foo with two argument variables of types
real. The arguments are named
sigma, but that is not part of the declaration. Two user-defined functions may not have the same name even if they have different sequences of argument types.