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c++gcc

C99 designator member outside of aggregate initializer

struct Foo {
    char a[10];
    int b;
};

static Foo foo = {.a="bla"};

Compiling the above code gives the following gcc error:

$ gcc -std=gnu++2a test.cpp 

C99 designator ‘a’ outside aggregate initializer

I thought that c-string designators in initializer list like these are ok in C++20? What am I missing? I am using gcc version 10.

Solution

  • This is a known bug with GCC: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55227

    Unfortunately, you will have to either not use designated initializers or use a different initializer for the array:

    static Foo foo = {"bla"};
static Foo foo = {.a={'b', 'l', 'a', 0}};

// Or if you can change Foo:
struct Foo {
    std::array<char, 10> a;
    int b;
};
static Foo foo = {.a={"bla"}};

    This appears to have been fixed in GCC 11.3 if you can upgrade your compiler.