system calls: signalfd () and the more recent signalfd4 (). The former system call does not implement ... signalfd () wrapper function will use signalfd4 () where it is available. …system calls: signalfd () and the more recent signalfd4 (). The former system call does not implement ... signalfd () wrapper function will use signalfd4 () where it is available. …signal (2) 1.0 signalfd (2) 2.6.22 signalfd4 (2) 2.6.27 sigpending (2) 1.0 sigprocmask