File	Date	Author	Commit
README.txt	2014-03-08	Guilherme Maciel Ferreira	[b654b8] Explain the difference between function styles,...

Read Me

Advanced C Tips and Techniques

The book was published on 1988, before the ANSI 9899:1989 (C89) standard.
Then, it uses old-style functions instead of the new-style introduced by ANSI.

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A.8.6.3 Function Declarators
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In a new-style function declaration T D where D has the form:

    D1 ( parameter-type-list )

As a special case, the declarator for a new-style function with no parameters
has a parameter list consisting soley of the keyword void. If the parameter
list ends with an ellipsis (, ...), then the function may accept more arguments
than the number of parameters explicitly described.

In an old-style function declaration T D where D has the form:

    D1 ( identifier-list(opt) )

In the old-style declarator, the identifier list must be absent unless the
declarator is used in the head of a function definition. No information about
the types of the parameters is supplied by the declaration.

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A.10.1 Function Definitions
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Function definitions have the form:

    function-definition:
        declaration-specifiers(opt) declarator declaration-list(opt) compound-statement

    declarator:
        pointer(opt) direct-declarator

    direct-declarator:
        direct-declarator ( parameter-type-list )
        direct-declarator ( identifier-list(opt) )

In the first form of direct-declarator, the function-definition is a new-style
function, and its parameters, together with their types, are declared in its
parameter-type-list; the declaration-list following the function's declarator
must be absent.

In the second form, the function-definition is old-style: the identifier-list
names the parameters, while the declaration-list attributes types to them. If
no declaration is given for a parameter, its type is taken to be int.

The new-style function definition is:

    int max(int a, int b, int c)
    {
    }

The corresponding old-style definition would be:

    int max(a, b, c)
    int a, b, c;
    {
    }