array incomplete type not allowed ?

[stav]

so this code works fine:

private:
	GLuint vertexBufferID;
	GLuint elementBufferID;



	GLfloat verts[] =
	{
		0.0f, 1.0f,
		-1.0f,-1.0f,
		1.0f,-1.0f
	};



public:
	Drawable();
	~Drawable();

	void Draw();

but as soon as i add another array, i get an "incomplete type not allowed" error?

private:
	GLuint vertexBufferID;
	GLuint elementBufferID;

	GLushort elements[] =
	{
		0,1,2
	};

	GLfloat verts[] =
	{
		0.0f, 1.0f,
		-1.0f,-1.0f,
		1.0f,-1.0f
	};



public:
	Drawable();
	~Drawable();

	void Draw();

[JLBorges]

'Flexible array member' is a C99 feature (thre must be only one such member and it must be the last member of the struct). https://en.wikipedia.org/wiki/Flexible_array_member

This is not allowed in standard C++. http://coliru.stacked-crooked.com/a/29c6f202faaa628e

That your code compiled without errors when there was only one flexible array member is because the GNU/GNU-compatible compiler is by default not a conforming C++ compiler.

Specify the size of the arrays, and compile with a C++ compiler (specify these options):
g++ -std=c++14 -O3 -Wall -Wextra -pedantic-errors