A “function call” is an expression that includes the name of the function being called or the value of a function pointer and, optionally, the arguments being passed to the function.
Syntax
postfix-expression :
postfix-expression ( argument-expression-list opt )
argument-expression-list :
assignment-expression
argument-expression-list , assignment-expression
The postfix-expression must evaluate to a function address (for example, a function identifier or the value of a function pointer), and argument-expression-list is a list of expressions (separated by commas) whose values (the “arguments”) are passed to the function. The argument-expression-list argument can be empty.
A function-call expression has the value and type of the function’s return value. A function cannot return an object of array type. If the function’s return type is void (that is, the function has been declared never to return a value), the function-call expression also has void type. (See Function Calls in Chapter 6 for more information.)