预定义常量

下列常量由此扩展定义，且仅在此扩展编译入 PHP 或在运行时动态载入时可用。

The following constants indicate the type of error returned by json_last_error().

JSON_ERROR_NONE (integer)

No error has occurred. Available since PHP 5.3.0.

JSON_ERROR_DEPTH (integer)

The maximum stack depth has been exceeded. Available since PHP 5.3.0.

JSON_ERROR_STATE_MISMATCH (integer)

Occurs with underflow or with the modes mismatch. Available since PHP 5.3.0.

JSON_ERROR_CTRL_CHAR (integer)

Control character error, possibly incorrectly encoded. Available since PHP 5.3.0.

JSON_ERROR_SYNTAX (integer)

Syntax error. Available since PHP 5.3.0.

JSON_ERROR_UTF8 (integer)

Malformed UTF-8 characters, possibly incorrectly encoded. This constant is available as of PHP 5.3.1.

The following constants can be combined to form options for json_encode().

JSON_HEX_TAG (integer)

All < and > are converted to \u003C and \u003E. Available since PHP 5.3.0.

JSON_HEX_AMP (integer)

All &s are converted to \u0026. Available since PHP 5.3.0.

JSON_HEX_APOS (integer)

All ' are converted to \u0027. Available since PHP 5.3.0.

JSON_HEX_QUOT (integer)

All " are converted to \u0022. Available since PHP 5.3.0.

JSON_FORCE_OBJECT (integer)

Outputs an object rather than an array when a non-associative array is used. Especially useful when the recipient of the output is expecting an object and the array is empty. Available since PHP 5.3.0.

JSON_NUMERIC_CHECK (integer)

Encodes numeric strings as numbers. Available since PHP 5.3.3.

JSON_BIGINT_AS_STRING (integer)

Encodes large integers as their original string value. Available since PHP 5.4.0.

JSON_PRETTY_PRINT (integer)

Use whitespace in returned data to format it. Available since PHP 5.4.0.

JSON_UNESCAPED_SLASHES (integer)

Don't escape /. Available since PHP 5.4.0.

JSON_UNESCAPED_UNICODE (integer)

Encode multibyte Unicode characters literally (default is to escape as \uXXXX). Available since PHP 5.4.0.