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