mx_getopt.h: Initializers use same designator multiple times. Is this defined behavior?

[donald]

mxq/mx_getopt.h

Line 87 in 3a519d7

#define MX_OPTION(...) { MX_OPTION_DEFAULTS, ## __VA_ARGS__ }

To initialize a field multiple times by repeating a C11 designator seems to produce the expected results (last initalization is used). Gcc explicitly mentions that in its manual [1]. Clang produces the same code [2]. Probably all reasonable compilers will do so.

However, currently clang generates a warning ("initializer overrides prior initialization of this subobject [-Winitializer-overrides]") and gcc does so with -Wextra ("initialized field overwritten [-Woverride-init]"). I'm not sure about the standard, but the warnings might hint, that the standard does not define this.

[1]: https://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html bottom of page
[2]: https://godbolt.org/z/so7KEv94T

[donald]

Merged commit 3f89869 ("Makefile: Enable -Wextra") includes -Wno-override-init.