ref: ec4c79f3a6ed97ec0c407a870827382cbefb1166
dir: /include/bits/darwin/amd64/arch/sigaction.h/
typedef unsigned int sigset_t; typedef struct siginfo siginfo_t; struct sigaction { union { void (*__sa_handler)(int); void (*__sa_sigaction)(int, siginfo_t *, void *); } __sigaction_u; sigset_t sa_mask; int sa_flags; }; #define sa_handler __sigaction_u.__sa_handler #define sa_sigaction __sigaction_u.__sa_sigaction