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CHAPTER 5 OPERATORS AND EXPRESSIONS

User’s Manual U15556EJ1V0UM

(2) Function call operators

Postfix Operators

( ) Function Call

FUNCTION

The postfix ( ) operator calls a function. The function to be called is specified with a postfix expression and

argument(s) to be passed to the function are indicated in parentheses ( ).

The description related to function includes the function prototype declaration, the function definition (the body of

a function), and the function call. The function prototype declaration specifies the value a function returns, the

type of argument, and the storage class.

If the function prototype declaration is not referred to in a function call, each argument is extended with a general

integer. This is called “default actual argument extension”. Performing a function prototype declaration avoids

default actual argument extension and detects errors in of the type and number of arguments and the type of

return value.

Calling a function that has neither a storage class specification nor a data type specification such as “identifier (

);” is interpreted as calling a function that has an external object and returns an int type that has no information

on arguments. In other words, the following declaration will be made implicitly.

extern int

identifier ( ) ;

SYNTAX

postfix-expression (argument-expression list);

[Example of function call]

int

func (char, int);

/* function prototype declaration */

char a ;

int b, ret;

void main(void){

ret = func(a, b);

/* function call */

}

int func(char c, int i) {

/* function definition */

return I;

}

NOTE

A function that returns an object other than array types can be called with this operator. The postfix expression

must be of a pointer type to this function.

In a function call including a prototype, the type of argument must be of a type that can be assigned to the

corresponding parameter(s). The number of arguments must also be in agreement.

78IV Datasheet(PDF) 75 Page - NEC