Are flexible array members valid in C++?

Question

In C99, you can declare a flexible array member of a struct as such: ``` struct blah { int foo[]; }; ``` However, when someone here at work tried to compile some code using clang in C++, that syntax did not work. (It had been working with MSVC.) We had to convert it to: ``` struct blah { int foo[0]; }; ``` Looking through the C++ standard, I found no reference to flexible member arrays at all; I always thought `[0]` was an invalid declaration, but apparently for a flexible member array it is valid. Are flexible member arrays actually valid in C++? If so, is the correct declaration `[]` or `[0]`?

Accepted Answer

C++ was first standardized in 1998, so it predates the addition of flexible array members to C (which was new in C99). There was a corrigendum to C++ in 2003, but that didn't add any relevant new features. The next revision of C++ (C++2b) is still under development, and it seems flexible array members still aren't added to it.

Are flexible array members valid in C++?

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