But as of PHP7 that's definitely no longer true. Well, that was probably true in old versions of PHP. There's a LOT of misinformation here, which I want to correct! Many people have warned against using strlen(), because it is "super slow". So it would seem you need either is_null() or isset() in addition to strlen() if you care whether or not the original value was null. !is_null(): $bar is truly an empty string If ( strlen ( $bar ) = 0 & isset( $bar )) echo 'isset(): $bar is truly an empty string ' If ( strlen ( $bar ) = 0 & ! is_null ( $bar )) echo '!is_null(): $bar is truly an empty string ' If ( strlen ( $foo ) = 0 & isset( $foo )) echo 'isset(): $foo is truly an empty string ' Įlse echo 'isset(): $foo is probably null ' If ( strlen ( $foo ) = 0 & ! is_null ( $foo )) echo '!is_null(): $foo is truly an empty string ' Įlse echo '!is_null(): $foo is probably null ' If ( $len = 0 ) echo 'Null length is still Zero ' If ( strlen ( $foo ) = 0 ) echo 'Null length is Zero ' So how do you know if the value was null, or truly an empty string? I would like to demonstrate that you need more than just this function in order to truly test for an empty string. If so, then you are likely experiencing this changed behavior. Strlen() expects parameter 1 to be string, array given in /var/www/sis/lib/functions/advanced_search_lib.php on line 1028
This likely affects other functions, so if you are getting different behaviors or new bugs suddenly, check if you have upgraded to 5.3 (which we did recently), and then check for some warnings in your logs like this: So, in PHP 5.3, strlen($attributes) returns NULL, while in PHP 5.2, strlen($attributes) returns the integer 5. There are some exceptions to this rule, such as the get_class() function, which will continue to return FALSE on error." This parameter parsing API causes functions to return NULL when passed incompatible parameters. "The newer internal parameter parsing API has been applied across all the extensions bundled with PHP 5.3.x.
In 5.3, this changed, as noted in the following point in the backward incompatible changes in 5.3 ( ): This is because in 5.2 strlen will automatically cast anything passed to it as a string, and casting an array to a string yields the string "Array". We just ran into what we thought was a bug but turned out to be a documented difference in behavior between PHP 5.2 & 5.3.
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The database column is in another character set (UTF-16, ISO-8859-1, etc.) with a length defined in characters / code points.įind the character set used, and pass it explicitly to the length function. The database column has a length defined in bytes (e.g. mysql varchar(200) for a utf-8 database).Ģ. Most likely case: the database column is UTF-8 with a length defined in unicode code points (e.g. When checking for length to make sure a value will fit in a database field, be mindful of using the right function.ġ.
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