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

shmop_read() - Read data from shared memory block

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>';