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addcslashes

(PHP 4, PHP 5)

addcslashes -- Quote string with slashes in a C style

Description

string addcslashes ( string str, string charlist )

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

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. In PHP \0 (NULL), \r (carriage return), \n (newline) and \t (tab) are predefined escape sequences, while in C all of these are predefined escape sequences.

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

Example 1. addcslashes() example

<?php
$escaped = addcslashes($not_escaped, "\0..\37!@\177..\377");
?>

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

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

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.

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

See also stripcslashes(), stripslashes(), htmlspecialchars(), and quotemeta().

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