C11 _Generic: how to deal with string literals?

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Here is a solution:

#include <stdio.h>
#define foo(x) _Generic((0,x), char*: puts(x))

int main()
{
    foo("Hello, world!");
    return 0;
}

This compiles and produces:

$ clang t.c && ./a.out 
Hello, world!

It is somewhat lame, but I did not find any better way to make x decay to a pointer to char nor to match its type in the fuzzy fashion that you require, with Apple LLVM version 4.2 (clang-425.0.28) (based on LLVM 3.2svn).

According to this blog post by Jens Gustedt, GCC’s behavior is different (in GCC, strings automatically decay to pointer in a _Generic context, apparently).

By the way, in C, the type of a string literal is array of char, not of const char. Rejecting char [] as type-name in a generic-association is not a compiler bug:

A generic selection shall have no more than one default generic association. The type name in a generic association shall specify a complete object type other than a variably modified type. (6.5.1.1:2 with my emphasis)

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