shm_get_var()

(PHP 4, PHP 5, PHP 7)

Returns a variable from shared memory

说明

shm_get_var()returns the variable with a given$variable_key, in the given shared memory segment. The variable is still present in the shared memory.

参数

Shared memory segment, obtained from shm_attach().

The variable key.

返回值

Returns the variable with the given key.

参见

• shm_has_var()Check whether a specific entry exists
• shm_put_var()Inserts or updates a variable in shared memory

hello everyone i came up with some sort of solution to the shm_get_var() 
returns false on error/returns a boolean false variable problem.
test script

class for using the shm_ functions & class for storing boolean values

A fully functional sample ...

To follow up on the posts by anonymous, Bob Van Zant and chris at free-source dot com below (or, as must people inexplicably write, above) regarding the PHP warning and FALSE that shm_get_var returns if the variable key doesn't exist:
My tests (with PHP4.3.4) show that defined() is useless here. Because the function defined(string) checks whether the constant whose name is string exists, the code 

works, provided the object that was stored isn't actually FALSE (via )
It would be nice to have a completely air-tight solution, though. D'oh!

You will still receive a notice use @:
if(!defined(@shm_get_var($mutex, $mutex_key))) {
    shm_put_var($mutex, $mutex_key, 0);
}

This seems to work fine to detect the lack of presence of a key in shared memory and then init it to 0 when found:
if(!defined(shm_get_var($mutex, $mutex_key))) {
    shm_put_var($mutex, $mutex_key, 0);
}

If any body has problem with shm_get_var();
this code correctly work with boolean-values^

I was annoyed by this warning when using shm_get_var():
Warning: shm_get_var() [function.shm-get-var]: variable key 2 doesn't exist in PATH_TO_FILE on line 64.
You can suppress the warning by changing the error reporting level. To do this for just the page in question, include the following line:

For more info: http://us.php.net/error_reporting