Creating arrays within functions in PHP

[Abhyro]

Hi

 

Is it a good practice to create an array withing a function?

Also wanted to know how the variables declared within a function behave in PHP. Are these variables destroyed once the function call is over or do they still cling on to the memory allocated to them? In case they are not destroyed it appears to me that with every call that is made to the function, more and more memory would be consumed and finally the program will crash. If this is the case arrays within functions can cause big problems....if anyone can shed light on this it will be of great help....my code has an array which is created withing a function and the program is just crashing without any error msg....hence am suspecting the above mentioned behavior.

 

Thanks

Abhijeet

[teynon]

Abhyro,

 

  I wasn't sure of the answer, so I did a test.

 

<?php

function test($x) {
	$var[$x]="blah";
}


for ($x=0; $x<20; $x++) {
	$myArray[$x]=1;

	echo "Loop 1 #{$x} = ".memory_get_usage() ."<br />";
}

for ($x=0; $x<20; $x++) {
	test($x);

	echo "Loop 2 #{$x} = ".memory_get_usage() ."<br />";
}
?>

 

The results are this:

 

Loop 1 #0 = 89056

Loop 1 #1 = 89144

Loop 1 #2 = 89216

Loop 1 #3 = 89288

Loop 1 #4 = 89360

Loop 1 #5 = 89432

Loop 1 #6 = 89504

Loop 1 #7 = 89576

Loop 1 #8 = 89648

Loop 1 #9 = 89720

Loop 1 #10 = 89792

Loop 1 #11 = 89864

Loop 1 #12 = 89936

Loop 1 #13 = 90008

Loop 1 #14 = 90080

Loop 1 #15 = 90152

Loop 1 #16 = 90224

Loop 1 #17 = 90296

Loop 1 #18 = 90368

Loop 1 #19 = 90440

Loop 2 #0 = 90776

Loop 2 #1 = 90776

Loop 2 #2 = 90776

Loop 2 #3 = 90776

Loop 2 #4 = 90776

Loop 2 #5 = 90776

Loop 2 #6 = 90776

Loop 2 #7 = 90776

Loop 2 #8 = 90776

Loop 2 #9 = 90776

Loop 2 #10 = 90776

Loop 2 #11 = 90776

Loop 2 #12 = 90776

Loop 2 #13 = 90776

Loop 2 #14 = 90776

Loop 2 #15 = 90776

Loop 2 #16 = 90776

Loop 2 #17 = 90776

Loop 2 #18 = 90776

Loop 2 #19 = 90776

 

So, as you can see, the variables inside the function are being destroyed.

[teynon]

Also, if your program is crashing without an error message, you should enable errors. Or you can check your servers PHP error log.