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json_last_error

(PHP 5 >= 5.3.0)

json_last_errorReturns the last error occurred

Description

int json_last_error ( void )

Returns the last error (if any) occurred during the last JSON encoding/decoding.

Parameters

This function has no parameters.

Return Values

Returns an integer, the value can be one of the following constants:

JSON error codes
Constant Meaning Availability
JSON_ERROR_NONE No error has occurred  
JSON_ERROR_DEPTH The maximum stack depth has been exceeded  
JSON_ERROR_STATE_MISMATCH Invalid or malformed JSON  
JSON_ERROR_CTRL_CHAR Control character error, possibly incorrectly encoded  
JSON_ERROR_SYNTAX Syntax error  
JSON_ERROR_UTF8 Malformed UTF-8 characters, possibly incorrectly encoded PHP 5.3.3
JSON_ERROR_RECURSION One or more recursive references in the value to be encoded PHP 5.5.0
JSON_ERROR_INF_OR_NAN One or more NAN or INF values in the value to be encoded PHP 5.5.0
JSON_ERROR_UNSUPPORTED_TYPE A value of a type that cannot be encoded was given PHP 5.5.0

Examples

Example #1 json_last_error() example

<?php
// A valid json string
$json[] = '{"Organization": "PHP Documentation Team"}';

// An invalid json string which will cause an syntax 
// error, in this case we used ' instead of " for quotation
$json[] = "{'Organization': 'PHP Documentation Team'}";


foreach (
$json as $string) {
    echo 
'Decoding: ' $string;
    
json_decode($string);

    switch (
json_last_error()) {
        case 
JSON_ERROR_NONE:
            echo 
' - No errors';
        break;
        case 
JSON_ERROR_DEPTH:
            echo 
' - Maximum stack depth exceeded';
        break;
        case 
JSON_ERROR_STATE_MISMATCH:
            echo 
' - Underflow or the modes mismatch';
        break;
        case 
JSON_ERROR_CTRL_CHAR:
            echo 
' - Unexpected control character found';
        break;
        case 
JSON_ERROR_SYNTAX:
            echo 
' - Syntax error, malformed JSON';
        break;
        case 
JSON_ERROR_UTF8:
            echo 
' - Malformed UTF-8 characters, possibly incorrectly encoded';
        break;
        default:
            echo 
' - Unknown error';
        break;
    }

    echo 
PHP_EOL;
}
?>

The above example will output:

Decoding: {"Organization": "PHP Documentation Team"} - No errors
Decoding: {'Organization': 'PHP Documentation Team'} - Syntax error, malformed JSON

Example #2 json_last_error() with json_encode()

<?php
// An invalid UTF8 sequence
$text "\xB1\x31";

$json  json_encode($text);
$error json_last_error();

var_dump($json$error === JSON_ERROR_UTF8);
?>

The above example will output:

string(4) "null"
bool(true)

See Also

PHP Manual