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.

Process Control constants

WNOHANG (int)

WUNTRACED (int)

WCONTINUED (int)

WEXITED (int)

WSTOPPED (int)

WNOWAIT (int)

SIG_* constants

SIG_IGN (int)

SIG_DFL (int)

SIG_ERR (int)

SIGHUP (int)

SIGINFO (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)

SIGRTMIN (int)

SIGRTMAX (int)

SIG_BLOCK (int)

SIG_UNBLOCK (int)

SIG_SETMASK (int)

SIGCKPT (int)

Generates/restores a checkpoint. Available from PHP 8.4.0 (DragonFlyBSD only).

SIGCKPTEXIT (int)

Generates/restores a checkpoint and exit. Available from PHP 8.4.0 (DragonFlyBSD only).

SI_* constants

SI_USER (int)

SI_NOINFO (int)

SI_KERNEL (int)

SI_QUEUE (int)

SI_TIMER (int)

SI_ASYNCIO (int)

SI_SIGIO (int)

SI_TKILL (int)

SI_MESGQ (int)

CLD_* constants

CLD_EXITED (int)

CLD_KILLED (int)

CLD_DUMPED (int)

CLD_TRAPPED (int)

CLD_STOPPED (int)

CLD_CONTINUED (int)

TRAP_* constants

TRAP_BRKPT (int)

TRAP_TRACE (int)

POLL_* constants

POLL_IN (int)

POLL_OUT (int)

POLL_MSG (int)

POLL_ERR (int)

POLL_PRI (int)

POLL_HUP (int)

ILL_* constants

ILL_ILLOPC (int)

ILL_ILLOPN (int)

ILL_ILLADR (int)

ILL_ILLTRP (int)

ILL_PRVOPC (int)

ILL_PRVREG (int)

ILL_COPROC (int)

ILL_BADSTK (int)

FPE_* constants

FPE_INTDIV (int)

FPE_INTOVF (int)

FPE_FLTDIV (int)

FPE_FLTOVF (int)

FPE_FLTUND (int)

FPE_FLTRES (int)

FPE_FLTINV (int)

FPE_FLTSUB (int)

SEGV_* constants

SEGV_MAPERR (int)

SEGV_ACCERR (int)

BUS_* constants

BUS_ADRALN (int)

BUS_ADRERR (int)

BUS_OBJERR (int)

CLONE_* constants

CLONE_NEWNS (int)

Available as of PHP 7.4.0

CLONE_NEWIPC (int)

Available as of PHP 7.4.0

CLONE_NEWUTS (int)

Available as of PHP 7.4.0

CLONE_NEWNET (int)

Available as of PHP 7.4.0

CLONE_NEWPID (int)

Available as of PHP 7.4.0

CLONE_NEWUSER (int)

Available as of PHP 7.4.0

CLONE_NEWCGROUP (int)

Available as of PHP 7.4.0

PRIO_* constants

PRIO_PGRP (int)

PRIO_USER (int)

PRIO_PROCESS (int)

PRIO_DARWIN_BG (int)

Available as of PHP 8.1.0.

PRIO_DARWIN_THREAD (int)

Available as of PHP 8.1.0.

Process Control error constants

Constants	Description
PCNTL_E2BIG (int)	Argument list too long
PCNTL_EACCES (int)	Permission denied
PCNTL_EAGAIN (int)	Resource temporarily unavailable
PCNTL_ECAPMODE (int)	The process attempted an operation not permitted in capability mode while running in capability mode.
PCNTL_ECHILD (int)	No child processes
PCNTL_EFAULT (int)	Bad address
PCNTL_EINTR (int)	Interrupted function call
PCNTL_EINVAL (int)	Invalid argument
PCNTL_EIO (int)	Input/output error
PCNTL_EISDIR (int)	Is a directory
PCNTL_ELIBBAD (int)	Accessing a corrupted shared library.
PCNTL_ELOOP (int)	Too many levels of symbolic links
PCNTL_EMFILE (int)	Too many open files. Commonly caused by exceeding the RLIMIT_NOFILE resource limit. Can also be caused by exceeding the limit specified in /proc/sys/fs/nr_open.
PCNTL_ENAMETOOLONG (int)	Filename too long
PCNTL_ENFILE (int)	Too many open files in system. On Linux, this is probably a result of encountering the /proc/sys/fs/file-max limit.
PCNTL_ENOENT (int)	No such file or directory. Typically, this error results when a specified pathname does not exist, or one of the components in the directory prefix of a pathname does not exist, or the specified pathname is a dangling symbolic link.
PCNTL_ENOEXEC (int)	Exec format error
PCNTL_ENOMEM (int)	Not enough space/cannot allocate memory
PCNTL_ENOSPC (int)	No space left on device
PCNTL_ENOTDIR (int)	Not a directory
PCNTL_EPERM (int)	Operation not permitted
PCNTL_ESRCH (int)	No such process
PCNTL_ETXTBSY (int)	Text file busy
PCNTL_EUSERS (int)	Too many users

FORK_* constants

FORK_NOSIGCHLD (int)

FORK_WAITPID (int)

RF* constants

RFCFDG (int)

RFFDG (int)

RFLINUXTHPN (int)

RFNOWAIT (int)

RFPROC (int)

RFTHREAD (int)

RFTSIGZMB (int)

First argument to waitid (idtype)

P_ALL (int)

Select any children.

P_PID (int)

Select by process ID.

P_PGID (int)

Select by process group ID.

P_PIDFD (int)

Select by PID file descriptor. Specific to Linux (since Linux 5.4).

P_UID (int)

Select by effective user ID. Specific to NetBSD and FreeBSD.

P_GID (int)

Select by effective group ID. Specific to NetBSD and FreeBSD.

P_SID (int)

Select by session ID. Specific to NetBSD and FreeBSD.

P_JAILID (int)

Select by jail identifier. Specific to FreeBSD.