preg_last_error

andre at koethur dot de (2013-06-23 09:00:43)

Just an addition to my previous note: In unicode mode (with "u" modifier), PREG_BAD_UTF8_ERROR only reflects errors in the subject string. If the pattern itself contains invalid characters, preg_match() (or preg_match_all()) returns false but preg_last_error() returns 0 indicating PREG_NO_ERROR. Instead, php issues a warning: "preg_match(): Compilation failed: invalid UTF-8 string at offset 0"

andre at koethur dot de (2013-06-18 12:37:13)

Here is a more advanced function to convert an error code to text:

<?php

function preg_errtxt($errcode)
{
    static $errtext;

    if (!isset($errtxt))
    {
        $errtext = array();
        $constants = get_defined_constants(true);
        foreach ($constants['pcre'] as $c => $n) if (preg_match('/_ERROR$/', $c)) $errtext[$n] = $c;
    }

    return array_key_exists($errcode, $errtext)? $errtext[$errcode] : NULL;
}

?>

Omer (2011-02-12 09:22:17)

here's the code to check for all errors
<?php
if (preg_last_error() == PREG_NO_ERROR) {
    print 'There is no error.';
}
else if (preg_last_error() == PREG_INTERNAL_ERROR) {
    print 'There is an internal error!';
}
else if (preg_last_error() == PREG_BACKTRACK_LIMIT_ERROR) {
    print 'Backtrack limit was exhausted!';
}
else if (preg_last_error() == PREG_RECURSION_LIMIT_ERROR) {
    print 'Recursion limit was exhausted!';
}
else if (preg_last_error() == PREG_BAD_UTF8_ERROR) {
    print 'Bad UTF8 error!';
}
else if (preg_last_error() == PREG_BAD_UTF8_ERROR) {
    print 'Bad UTF8 offset error!';
}
?>

johan at bluemoonit dot net (2010-05-24 05:20:24)

The above function pcre_error_deocde [sic] is not correct - not all of the used constants are errors constants. For example, when the error is actually PREG_BAD_UTF8_ERROR, the function outputs the text for PREG_SPLIT_OFFSET_CAPTURE.