What difference does usage of symbol @ with ini_set, built-in function makes in PHP?

Question

In one of my project's configuration settings I observed following two lines at the beginning of file :

@ini_set('memory_limit', '-1');
@set_time_limit(0);

My doubt is what's the difference in the above two lines of code and following lines of code?

ini_set('memory_limit', '-1');
set_time_limit(0);

What's the intention of prefixing @ symbol in PHP?

Please provide me in detail and to the point answer.

Thanks in advance.

Uhm, I didn't know those functions needed an error suppressor? — Damien Pirsy, Dec 25 '14 at 08:13
@DamienPirsy They do when you try to set a value when you are using PHP in safe mode or when the functions are disabled. — Ismael Miguel, Dec 25 '14 at 08:13
@IsmaelMiguel Nice, I didn't know that, I thought they were quite universally appliable — Damien Pirsy, Dec 25 '14 at 08:15
@DamienPirsy It is in the documentation. Try running that code on http://writecodeonline.com/php and you will see the warnings. — Ismael Miguel, Dec 25 '14 at 08:31

score 10 · Accepted Answer · answered Dec 25 '14 at 08:13

10

@ in php is simply for silencing errors.

for example:

<?php
    $x = 5;
    $y = @$z;

so $y will be null

if you remove the @ it will throw an error.

answered Dec 25 '14 at 08:13

Tzook Bar Noy

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You forgot to mention that the `error_reporting` value in `php.ini` must have the 'bit-flag' `E_WARNING` (value `2`) on it's value. For example, the value `E_ALL`. Check http://php.net/manual/en/function.error-reporting.php for more about this. – Ismael Miguel Dec 25 '14 at 08:47
thanks for the comment, now others will see it as well. – Tzook Bar Noy Dec 28 '14 at 10:13

score 3 · Answer 2 · answered Dec 25 '14 at 08:16

3

Error Control Operators

PHP supports one error control operator: the at sign (@). When prepended to an expression in PHP, any error messages that might be generated by that expression will be ignored.

Error Control Operators

answered Dec 25 '14 at 08:16

i'm PosSible

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What difference does usage of symbol @ with ini_set, built-in function makes in PHP?

2 Answers2