error: too many initializers for a struct

Question

I'm trying some code with c++11,

  struct Data {};

  struct B {
    B(Data data) : m_data{data} {}
    Data m_data{};
  };

it complains error: too many initializers for 'Data'

what is wrong?

[UPDATE] thanks guys, there is something wrong with my toolchain configuration.

Answer 1

You get that error string when you do not enable c++11 mode or later in older GCC compilers (that defaults to c++03).

 main.cpp:4:31: error: too many initializers for 'Data' B(Data data) : m_data{data} {} 

See it here . Although newer versions of GCC will give you more helpful diagnostics to enable c++11 mode.

So, just add to your compiler invocation:

-std=c++11

Answer 2

That's correct c++11, but maybe you are not compiling in C++11 mode.

Many compiler still defaults to C++98, and you typically need to activate a command line switch (or an option in your IDE) to enable C++11 syntax.

I've added to your code a small main:

int main()
{
    Data d;
    B b(d);
}

... and it compiles clean both with gcc 5.x and clang 802 (xcode 8 version), provided I add on the command line:

-std=c++11