These are called desginated initializers, they're part of C99.[0] This is a good read which discusses them and also devles into compound literals.[1] [0] https

These are called desginated initializers, they're part of C99.[0] This is a good read which discusses them and also devles into compound literals.[1] [0] https://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html https://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html [1] https://nickdesaulniers.github.io/blog/2013/07/25/designated-initialization-with-pointers-in-c/ https://nickdesaulniers.github.io/blog/2013/07/25/designated...