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Process Control Functions

소개

Process Control support in PHP implements the Unix style of process creation, program execution, signal handling and process termination. Process Control should not be enabled within a web server environment and unexpected results may happen if any Process Control functions are used within a web server environment.

This documentation is intended to explain the general usage of each of the Process Control functions. For detailed information about Unix process control you are encouraged to consult your systems documentation including fork(2), waitpid(2) and signal(2) or a comprehensive reference such as Advanced Programming in the UNIX Environment by W. Richard Stevens (Addison-Wesley).

PCNTL now uses ticks as the signal handle callback mechanism, which is much faster than the previous mechanism. This change follows the same semantics as using "user ticks". You use the declare() statement to specify the locations in your program where callbacks are allowed to occur. This allows you to minimize the overhead of handling asynchronous events. In the past, compiling PHP with pcntl enabled would always incur this overhead, whether or not your script actually used pcntl.

There is one adjustment that all pcntl scripts prior to PHP 4.3.0 must make for them to work which is to either to use declare() on a section where you wish to allow callbacks or to just enable it across the entire script using the new global syntax of declare().

Note: 이 확장 모듈은 윈도우 플랫폼에서는 사용할 수 없습니다.

요구 조건

이 확장을 빌드할 때 외부 라이브러리가 필요하지 않습니다.

설치

Process Control support in PHP is not enabled by default. You have to compile the CGI or CLI version of PHP with --enable-pcntl configuration option when compiling PHP to enable Process Control support.

Note: Currently, this module will not function on non-Unix platforms (Windows).

실행시 설정

이 확장은 php.ini 설정이 존재하지 않습니다.

자원형

이 확장은 리소스형을 정의하지 않습니다.

예약 상수

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)

예제

This example forks off a daemon process with a signal handler.

Example#1 Process Control Example

<?php
declare(ticks=1);

$pid pcntl_fork();
if (
$pid == -1) {
     die(
"could not fork"); 
} else if (
$pid) {
     exit(); 
// we are the parent 
} else {
     
// we are the child
}

// detatch from the controlling terminal
if (posix_setsid() == -1) {
    die(
"could not detach from terminal");
}

// setup signal handlers
pcntl_signal(SIGTERM"sig_handler");
pcntl_signal(SIGHUP"sig_handler");

// loop forever performing tasks
while (1) {

    
// do something interesting here

}

function 
sig_handler($signo
{

     switch (
$signo) {
         case 
SIGTERM:
             
// handle shutdown tasks
             
exit;
             break;
         case 
SIGHUP:
             
// handle restart tasks
             
break;
         default:
             
// handle all other signals
     
}

}

?>

참고

A look at the section about POSIX functions may be useful.

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