Function declarations

A function declaration introduces an identifier that designates a function and, optionally, specifies the types of the function parameters (the prototype). Function declarations (unlike definitions) may appear at block scope as well as file scope.

# Notes

Unlike in C++, the declarators f() and f(void) have different meaning: the declarator f(void) is a new-style (prototype) declarator that declares a function that takes no parameters. The declarator f() is a declarator that declares a function that takes unspecified number of parameters (unless used in a function definition)

Unlike in a function definition, the parameter list may be inherited from a typedef

In C89, specifiers-and-qualifiers was optional, and if omitted, the return type of the function defaulted to int (possibly amended by the declarator).

# Defect reports

# See also

• C++ documentation