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JS_NewExternalString 编辑

Create a new JSString whose characters are stored in external memory.

Syntax

JSString *
JS_NewExternalString(JSContext *cx, const char16_t *chars, size_t length,
                     const JSStringFinalizer *fin);

JSString *
JS_NewExternalStringWithClosure(JSContext *cx, jschar *chars, size_t length,
                                int type, void *closure); // Obsolete since JSAPI 13

Name	Type	Description
`cx`	`JSContext *`	The context in which to create the new string. Requires request. In a `JS_THREADSAFE` build, the caller must be in a request on this `JSContext`.
`chars`	`const char16_t ` or `const jschar `	Pointer to the first element of an array of `char16_t`s. This array is used as the character buffer of the `JSString` to be created. The array must be populated with the desired character data before `JS_NewExternalString` is called, and the array must remain in memory, with its contents unchanged, for as long as the JavaScript engine needs to hold on to it. (Ultimately, the string will be garbage collected, and the JavaScript engine will call the string finalizer callback, allowing the application to free the array.) The array does not need to be zero-terminated.
`length`	`size_t`	The number of characters in the array `chars`.
`fin`	`JSStringFinalizer`	A string finalizer the JavaScript engine should use (later) to free the string buffer `chars`. Added in SpiderMonkey 17
`type`	`int`	(`JS_NewExternalStringWithClosure` only) Indicates which string finalizer callback the JavaScript engine should use (later) to free the string buffer `chars`. This must be an id number previously returned by a successful call to `JS_AddExternalStringFinalizer`. Obsolete since JSAPI 13
`closure`	`void *`	(`JS_NewExternalStringWithClosure` only) Arbitrary, application-defined data to include in the string object after it's created. If you use this as a pointer, you should clean it up in the external string finalizer that was previously set up using `JS_AddExternalStringFinalizer`. Obsolete since JSAPI 13

JS_NewExternalString and JS_NewExternalStringWithClosure create a new JSString whose characters are stored in external memory, i.e., memory allocated by the application, not the JavaScript engine. Since the program allocated the memory, it will need to free it; this happens in an external string finalizer indicated by the type parameter.

JS_NewExternalStringWithClosure works similarly, except it accepts an additional parameter, closure, which is saved in the string's internal data structure. It can be retrieved later by calling JS_GetExternalStringClosure. This is application-defined data you can associate with the string.

To determine if a string was created as an external string, you can call JS_IsExternalString.

JS_NewExternalString 编辑

Syntax

Description

See Also

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友情链接

JS_NewExternalString 编辑

Syntax

Description

See Also

如果你对这篇内容有疑问，欢迎到本站社区发帖提问 参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

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友情链接

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。