The
use of the const and volatile specifiers is only supported by
C++. A function declaration establishes the name and the parameters of the function.
/-------------\
|
>>----------------------------------function_declarator--(------------------->
|-extern-| \-type_specifier-/ \-parameter-/
\-static-/
>--)----------------><
|-const----|
\-volatile-/
The
use of the const and volatile specifiers is only supported by
C++.
A function is declared implicitly by its appearance in an expression if it has not been defined or declared previously; the implicit declaration is equivalent to a declaration of extern int func_name(). The default return type of a function is int.
To indicate that the function does not return a value, declare it with a return type of void.
A function
cannot be declared as returning a data object having a volatile
or const type but it can return a pointer to a volatile
or const object. Also, a function cannot return
a value that has a type of array or function.
If the
called function returns a value that has a type other than int,
you must declare the function before the function call. Even if a
called function returns a type int, explicitly
declaring the function prior to its call is good programming
practice.
Some declarations do not have parameter lists; the declarations simply specify the types of parameters and the return values, such as in the following example:
int func(int,long);
Example of
the main() Function
Examples of
Function Declarations
Examples of
Function Definitions
C++ Function
Declarations
main() Function
Function Definitions
