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I am trying to statically initialize a constexpr std::array of objects containing function pointers with the following code:

#include <array>

using TVoidVoid = void(*)(void);

class State
public:
 constexpr State(TVoidVoid function) : function_function
private:
 TVoidVoid function_;
;

void OnEvent1()
void OnEvent2()
constexpr std::array<State, 10> states = OnEvent1, OnEvent2;

int main()

I am compiling with:

g++ -Wall -Wextra -Wshadow -Weffc++ -Wstrict-aliasing -ansi -pedantic -Werror -std=c++14 main.cpp

I have trouble understanding the compiling error I'm getting:

main.cpp:14:69: error: too many initializers for ‘const std::array<State, 10>’
 constexpr std::array<State, 10> states = OnEvent1, OnEvent2

The compiler is g++ (Ubuntu 7.3.0-27ubuntu1~18.04) 7.3.0.

What could be the problem here? Many thanks in advance!

You need a default constructor (for the last 8)

#include <array>

using TVoidVoid = void(*)(void);

class State
public:
 // This static is equivalent to a TVoidVoid
 // used by the default constructor
 static void DefFunct() 

 constexpr State(TVoidVoid function) : function_function

 // We create a default constructor for the 
 // empty elemnts of the array with our function
 constexpr State() : function_(DefFunct) 

private:
 TVoidVoid function_;
;

void OnEvent1()
void OnEvent2()
constexpr std::array<State, 10> states = OnEvent1, OnEvent2;

int main()

The error message could be better. But what's tripping the initialization is in fact that you don't have enough braces. Recall that a std::array is an aggregate wrapping a raw array. So you need to initialize like this:

constexpr std::array<State, 10> states = OnEvent1, OnEvent2 ;

Otherwise, the somewhat inaccurate brace ellision detection algorithm assumes OnEvent1 is to initialize the internal array, and the second clause is redundant.

Now you just need to provide a default c'tor for State, or adjust the array size.