PHP 5.4.36 Released

preg_last_error

(PHP 5 >= 5.2.0)

preg_last_error直近の PCRE 正規表現処理のエラーコードを返す

説明

int preg_last_error ( void )

直近の PCRE 正規表現処理のエラーコードを返します。

例1 preg_last_error() の例

<?php

preg_match
('/(?:\D+|<\d+>)*[!?]/''foobar foobar foobar');

if (
preg_last_error() == PREG_BACKTRACK_LIMIT_ERROR) {
    print 
'Backtrack limit was exhausted!';
}

?>

上の例の出力は以下となります。

Backtrack limit was exhausted!

返り値

以下の定数のいずれかを返します (別のページで説明します)。

  • PREG_NO_ERROR
  • PREG_INTERNAL_ERROR
  • PREG_BACKTRACK_LIMIT_ERROR (pcre.backtrack_limit も参照ください)
  • PREG_RECURSION_LIMIT_ERROR (pcre.recursion_limit も参照ください)
  • PREG_BAD_UTF8_ERROR
  • PREG_BAD_UTF8_OFFSET_ERROR (PHP 5.3.0 以降)

add a note add a note

User Contributed Notes 5 notes

up
7
andre at koethur dot de
1 year ago
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;
}

?>
up
3
gk at anuary dot com
11 months ago
In PHP 5.5 and above, getting the error message is as simple as:

<?php
echo array_flip(get_defined_constants(true)['pcre'])[preg_last_error()];
up
1
johan at bluemoonit dot net
4 years ago
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.
up
-1
andre at koethur dot de
1 year ago
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"
up
-6
Omer
3 years ago
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!';
}
?>
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