PHP preg_last_error() Function

Example

Use preg_last_error() to handle errors:

<?php
$str = 'The regular expression is invalid.';
$pattern = '/invalid//';
$match = @preg_match($pattern, $str, $matches);

if($match === false) {
// An error occurred
$err = preg_last_error();
if($err == PREG_INTERNAL_ERROR) {
echo 'Invalid regular expression.';
}
} else if($match) {
// A match was found
echo $matches[0];
} else {
// No matches were found
echo 'No matches found';
}
?>

Definition and Usage

The preg_last_error() function returns an error code for the most recently evaluated regular expression. The returned value will match one of the following constants:

Constant	Description
PREG_NO_ERROR	No error occurred
PREG_INTERNAL_ERROR	There was an error evaluating the expression
PREG_BACKTRACK_LIMIT_ERROR	The number of backtracks needed to evaluate the expression exceeded the limit given in PHP's configuration
PREG_RECURSION_LIMIT_ERROR	The recursion depth needed to evaluate the expression exceeded the limit given in PHP's configuration
PREG_BAD_UTF8_ERROR	The input string contained invalid UTF-8 data
PREG_BAD_UTF8_OFFSET_ERROR	During evaluation, a string offset did not point to the first character of a multibyte UTF-8 symbol
PREG_JIT_STACKLIMIT_ERROR	The JIT compiler ran out of stack memory when trying to evaluate the expression

Syntax

preg_last_error()

Technical Details

Return Value:	Returns an error code for the most recently evaluated regular expression
PHP Version:	5.2.0+

❮ PHP RegExp Reference