Declare a function signature with decltype()

Question

Is it possible to declare a function bar to have the same signature as function foo?

int foo(int a)
{
    return 0; 
}

decltype(foo) bar
{
    return 1;
} //imaginary syntax

Answer 1

I think the same applies as for typedefs and aliases: You may use decltype to declare a function, but not to define it:

int foo();

decltype(foo) bar;

int foo()
{
    return bar();
}

int bar() { return 0; }

is accepted by clang++3.5 and g++4.8.1

---

[dcl.fct.def.general]/2 forbids (grammatically) the definition of a function w/o parentheses:

The declarator in a function-definition shall have the form

       D1 ( parameter-declaration-clause ) cv-qualifier-seq_opt ref-qualifier_opt exception-specification_opt attribute-specifier-seq_opt trailing-return-type_opt

as described in 8.3.5.