shm_put_var

(PHP 4, PHP 5)

shm_put_var — Inserts or updates a variable in shared memory

설명

bool shm_put_var ( resource $shm_identifier , int $variable_key , mixed $variable )

shm_put_var() inserts or updates the variable with the given variable_key .

Warnings (E_WARNING level) will be issued if shm_identifier is not a valid SysV shared memory index or if there was not enough shared memory remaining to complete your request.

인수

shm_identifier: A shared memory resource handle as returned by shm_attach()
variable_key: The variable key.
variable: The variable. All variable-types are supported.

반환값

성공할 경우 TRUE를, 실패할 경우 FALSE를 반환합니다.

참고

shm_get_var() - Returns a variable from shared memory
shm_has_var() - Check whether a specific entry exists

shm_remove_var

shm_has_var

Last updated: Fri, 24 Jul 2009

add a note User Contributed Notes
shm_put_var

ygbr at me dot com
12-Oct-2009 09:25


Will it ever support resource identifiers like pfsockopen() pointers?



The main problem is that when we run PHP as a Apache Module we never know in which process the next request will bind to, making impossible to have true persistent socket connections unless we can store the pointer to it or directly open the socket inode with fopen() like functions and retrieve the same resource pointer again.



I thought I could use shm, but it seems that shm doesn't allow o store resource pointers... sad... :(

Hendrik Klindworth
02-Feb-2009 04:28


shm_put_var has no protection against race conditions. If two scripts insert the same key at the same time php might segfault.

jasonrlester at yahoo dot com
25-Apr-2008 07:51


sadly troy is right



the following script will return:



resource(5) of type (stream)

int(0)



<?php



define("FOPEN_RESOURCE", 1);

define("FOPEN_FILEPATH", "/path/to/file");



$fopen_resource = fopen(FOPEN_FILEPATH, "w");



var_dump($fopen_resource);



$shm_id = shm_attach(1);

if ($shm_id === false)

{

    echo "Fail to attach shared memory.\n";

}



if (!shm_put_var($shm_id, FOPEN_RESOURCE, $fopen_resource))

{

    echo "Failed to put var 1 in shared memory $shm_id.\n";

}



$sm_fopen_resource = shm_get_var($shm_id, FOPEN_RESOURCE);

if ($sm_fopen_resource === false)

{

    echo "Failed to retreive fopen_resource from Shared memory\r\n";

}



var_dump($sm_fopen_resource);



if($shm_id) shm_remove($shm_id);

if($fopen_resource) fclose($fopen_resource);



?>

troy
06-Mar-2008 03:02


This isn't entirely accurate. Not all variable types are supported, you can't put a resource variable into shared memory.



When you try to take it out, it will be a zero.

tomlove at gmail dot com
30-Sep-2004 11:53


Use as few variable_keys as you can. With large arrays of data, rather make the array multi-dimensional and store under one variable_key than use variable_key as your index. The benefit is especially noticeable when repeated fetching from the end of the array is necessary and updates are less frequent.

add a note

shm_remove_var

shm_has_var

Last updated: Fri, 24 Jul 2009