12-06-2011
Signalsafe data structures
Hello,
I have a signal handler which manipulates a data structure. The data structure's operations aren't atomic. So if two threads/processes are in a critical section at the same time the data structure will be broken.
With threads you can avoid this stuff with semaphores etc.
However, signal handlers work a bit different than threads. If a signal handler is currently manipulating the data structure and during this the signal handler is called again, then the following happens:
It cannot access the data structure because the first signal handler has it locked, which results in a deadlock.
How can I avoid it but still manipulate my data structure? I cannot lose signals either.
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LEARN ABOUT PHP
array_replace
ARRAY_REPLACE(3) 1 ARRAY_REPLACE(3)
array_replace - Replaces elements from passed arrays into the first array
SYNOPSIS
array array_replace (array $array1, array $array2, [array $...])
DESCRIPTION
array_replace(3) replaces the values of $array1 with values having the same keys in each of the following arrays. If a key from the first
array exists in the second array, its value will be replaced by the value from the second array. If the key exists in the second array, and
not the first, it will be created in the first array. If a key only exists in the first array, it will be left as is. If several arrays are
passed for replacement, they will be processed in order, the later arrays overwriting the previous values.
array_replace(3) is not recursive : it will replace values in the first array by whatever type is in the second array.
PARAMETERS
o $array1
- The array in which elements are replaced.
o $array2
- The array from which elements will be extracted.
o $...
- More arrays from which elements will be extracted. Values from later arrays overwrite the previous values.
RETURN VALUES
Returns an array, or NULL if an error occurs.
EXAMPLES
Example #1
array_replace(3) example
<?php
$base = array("orange", "banana", "apple", "raspberry");
$replacements = array(0 => "pineapple", 4 => "cherry");
$replacements2 = array(0 => "grape");
$basket = array_replace($base, $replacements, $replacements2);
print_r($basket);
?>
The above example will output:
Array
(
[0] => grape
[1] => banana
[2] => apple
[3] => raspberry
[4] => cherry
)
SEE ALSO
array_replace_recursive(3), array_merge(3).
PHP Documentation Group ARRAY_REPLACE(3)