# Predefined Constants

The following list of signals are supported by the Process Control functions. Please see your systems signal(7) man page for details of the default behavior of these signals.

`WNOHANG` (int)
`WUNTRACED` (int)
`SIG_IGN` (int)
`SIG_DFL` (int)
`SIG_ERR` (int)
`SIGHUP` (int)
`SIGINT` (int)
`SIGQUIT` (int)
`SIGILL` (int)
`SIGTRAP` (int)
`SIGABRT` (int)
`SIGIOT` (int)
`SIGBUS` (int)
`SIGFPE` (int)
`SIGKILL` (int)
`SIGUSR1` (int)
`SIGSEGV` (int)
`SIGUSR2` (int)
`SIGPIPE` (int)
`SIGALRM` (int)
`SIGTERM` (int)
`SIGSTKFLT` (int)
`SIGCLD` (int)
`SIGCHLD` (int)
`SIGCONT` (int)
`SIGSTOP` (int)
`SIGTSTP` (int)
`SIGTTIN` (int)
`SIGTTOU` (int)
`SIGURG` (int)
`SIGXCPU` (int)
`SIGXFSZ` (int)
`SIGVTALRM` (int)
`SIGPROF` (int)
`SIGWINCH` (int)
`SIGPOLL` (int)
`SIGIO` (int)
`SIGPWR` (int)
`SIGSYS` (int)
`SIGBABY` (int)
`SIG_BLOCK` (int)
  Available since PHP 5.3.0.
`SIG_UNBLOCK` (int)
  Available since PHP 5.3.0.
`SIG_SETMASK` (int)
  Available since PHP 5.3.0.
`SI_USER` (int)
  Available since PHP 5.3.0.
`SI_NOINFO` (int)
  Available since PHP 5.3.0.
`SI_KERNEL` (int)
  Available since PHP 5.3.0.
`SI_QUEUE` (int)
  Available since PHP 5.3.0.
`SI_TIMER` (int)
  Available since PHP 5.3.0.
`SI_MSGGQ` (int)
  Available since PHP 5.3.0.
`SI_ASYNCIO` (int)
  Available since PHP 5.3.0.
`SI_SIGIO` (int)
  Available since PHP 5.3.0.
`SI_TKILL` (int)
  Available since PHP 5.3.0.
`CLD_EXITED` (int)
  Available since PHP 5.3.0.
`CLD_KILLED` (int)
  Available since PHP 5.3.0.
`CLD_DUMPED` (int)
  Available since PHP 5.3.0.
`CLD_TRAPPED` (int)
  Available since PHP 5.3.0.
`CLD_STOPPED` (int)
  Available since PHP 5.3.0.
`CLD_CONTINUED` (int)
  Available since PHP 5.3.0.
`TRAP_BRKPT` (int)
  Available since PHP 5.3.0.
`TRAP_TRACE` (int)
  Available since PHP 5.3.0.
`POLL_IN` (int)
  Available since PHP 5.3.0.
`POLL_OUT` (int)
  Available since PHP 5.3.0.
`POLL_MSG` (int)
  Available since PHP 5.3.0.
`POLL_ERR` (int)
  Available since PHP 5.3.0.
`POLL_PRI` (int)
  Available since PHP 5.3.0.
`POLL_HUP` (int)
  Available since PHP 5.3.0.
`ILL_ILLOPC` (int)
  Available since PHP 5.3.0.
`ILL_ILLOPN` (int)
  Available since PHP 5.3.0.
`ILL_ILLADR` (int)
  Available since PHP 5.3.0.
`ILL_ILLTRP` (int)
  Available since PHP 5.3.0.
`ILL_PRVOPC` (int)
  Available since PHP 5.3.0.
`ILL_PRVREG` (int)
  Available since PHP 5.3.0.
`ILL_COPROC` (int)
  Available since PHP 5.3.0.
`ILL_BADSTK` (int)
  Available since PHP 5.3.0.
`FPE_INTDIV` (int)
  Available since PHP 5.3.0.
`FPE_INTOVF` (int)
  Available since PHP 5.3.0.
`FPE_FLTDIV` (int)
  Available since PHP 5.3.0.
`FPE_FLTOVF` (int)
  Available since PHP 5.3.0.
`FPE_FLTUND` (int)
  Available since PHP 5.3.0.
`FPE_FLTRES` (int)
  Available since PHP 5.3.0.
`FPE_FLTINV` (int)
  Available since PHP 5.3.0.
`FPE_FLTSUB` (int)
  Available since PHP 5.3.0.
`SEGV_MAPERR` (int)
  Available since PHP 5.3.0.
`SEGV_ACCERR` (int)
  Available since PHP 5.3.0.
`BUS_ADRALN` (int)
  Available since PHP 5.3.0.
`BUS_ADRERR` (int)
  Available since PHP 5.3.0.
`BUS_OBJERR` (int)
  Available since PHP 5.3.0.