Function sigsuspend 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn sigsuspend(sigmask: *const sigset_t) -> c_int

See https://pubs.opengroup.org/onlinepubs/9799919799/functions/sigsuspend.html.

Atomically both replace the current signal mask of the calling thread with the set of signals pointed to by sigmask and suspend the thread until delivery of a signal whose action is either to execute a signal-catching function or to terminate the process.

Upon success, suspends thread execution and does not return. If the action is to execute a signal-catching function, returns -1 after the signal-catching function returns, and restores the signal mask back to the set that existed prior to calling this function, then sets errno to indicate the error. Upon failure, returns -1 and sets errno to indicate the error.