shmop_write

(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)

shmop_write — Write data into shared memory block

说明

shmop_write ( Shmop $shmop , string $data , int $offset ) : int

shmop_write() will write a string into shared memory block.

参数

shmop

The shared memory block identifier created by shmop_open()

data

A string to write into shared memory block

offset

Specifies where to start writing data inside the shared memory segment.

返回值

The size of the written data.

更新日志

版本 说明
8.0.0 Prior to PHP 8.0.0, false was returned on failure.
8.0.0 shmop expects a Shmop instance now; previously, a resource was expected.

范例

Example #1 Writing to shared memory block

<?php
$shm_bytes_written = shmop_write($shm_id, $my_string, 0);
?>

This example will write data inside $my_string into shared memory block, $shm_bytes_written will contain the number of bytes written.

参见

User Contributed Notes

radupb at yahoo dot com 30-Nov-2020 09:13
I guess pack-unpack are the handy functions for encoding/decoding data as/from a binary string for shmop_write/shmop_read. Example:

$format='LLLLSSCCCC';  //data format for pack
$key=1;
if( !($shmid=shmop_open($key,'n',0660,30)) )
  die('shmop_open failed.');

//my data to encode:
$hd=array('ALIVE1'=>1,'ALIVE2'=>2,'ALIVE3'=>3,'ALIVE4'=>4,
      'CRTPTR'=>5,'CRTSEQ'=>6,
      'CTW'=>7,'LOCK'=>8,'PLAY'=>9,'MISS'=>10
);

$tmp=pack( $format, $hd['ALIVE1'],$hd['ALIVE2'],$hd['ALIVE3'],$hd['ALIVE4'],  $hd['CRTPTR'],$hd['CRTSEQ'],$hd['CTW'],$hd['LOCK'],$hd['PLAY'],$hd['MISS'] );

if( ($w=shmop_write($shmid,$tmp,0))!=24 )
  die('write error $w='.$w);

And reading from some other process:
$key=1;
if( !($shmid=shmop_open($key,'w',0,0)) )
  die('shmop_open failed.');

$formatR='L4ALIVE/SCRTPTR/SCRTSEQ/CCTW/CLOCK/CPLAY/CMISS'; //data format for unpack

$hd=unpack( $formatR, shmop_read( $shmid,0,24) );
echo'hd:<pre>';print_r($hd);echo'</pre>';