addcslashes

Description

Returns a string with backslashes before characters that are listed in characters parameter.

Parameters

string

The string to be escaped.

characters

A list of characters to be escaped. If characters contains characters \n, \r etc., they are converted in C-like style, while other non-alphanumeric characters with ASCII codes lower than 32 and higher than 126 converted to octal representation.

When you define a sequence of characters in the characters argument make sure that you know what characters come between the characters that you set as the start and end of the range.

addcslashes() with Ranges

phpCopy

<?php
echo addcslashes('foo[ ]', 'A..z');
// output:  \f\o\o\[ \]
// All upper and lower-case letters will be escaped
// ... but so will the [\]^_`
?>

Also, if the first character in a range has a higher ASCII value than the second character in the range, no range will be constructed. Only the start, end and period characters will be escaped. Use the ord() function to find the ASCII value for a character.

addcslashes() with Characters in Wrong Order

phpCopy

<?php
echo addcslashes("zoo['.']", 'z..A');
// output:  \zoo['\.']
?>

Be careful if you choose to escape characters 0, a, b, f, n, r, t and v. They will be converted to \0, \a, \b, \f, \n, \r, \t and \v, all of which are predefined escape sequences in C. Many of these sequences are also defined in other C-derived languages, including PHP, meaning that you may not get the desired result if you use the output of addcslashes() to generate code in those languages with these characters defined in characters.

Return Values

Returns the escaped string.

Examples

characters like "\0..\37", which would escape all characters with ASCII code between 0 and 31.

addcslashes() example

<?php
$not_escaped = "PHP isThirty\nYears Old!\tYay to the Elephant!\n";
$escaped = addcslashes($not_escaped, "\0..\37!@\177..\377");
echo $escaped;
?>

See Also

• stripcslashes()
• stripslashes()
• addslashes()
• htmlspecialchars()
• quotemeta()