| JS_GetInstancePrivate |
Function |
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Summary
Retrieves the private data associated with an object if that object is an instance of a class.
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Syntax
void * JS_GetInstancePrivate(JSContext *cx, JSObject *obj,
JSClass *clasp, jsval *argv);
| Name | Type | Description |
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cx | JSContext * | Pointer to a JS context from which to derive runtime information.
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obj | JSObject * | Object for which to retrieve private data.
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clasp | JSClass * | Class against which to test the object.
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argv | jsval * | Optional argument vector. If you do not want to pass an argument vector, pass NULL for this argument.
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Description
JS_GetInstancePrivate determines if a specified JS object, obj, is an instance of a JS class, clasp, and if it is, returns a pointer to the object's private data. If the object's internal class pointer corresponds to clasp, and you do not also pass an optional argument vector, argv, this function attempts to retrieve a pointer to the private data. Otherwise, it returns NULL.
If you pass a non-null argument vector, argv, to JS_GetInstancePrivate, and obj is not an instance of clasp, this function reports a class mismatch before returning NULL. In this case, JS_GetInstancePrivate tests whether or not there is a function name associated with the argument vector, and if there is, reports the name in an error message using the JS_ReportError function.
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Notes
If obj is an instance of clasp, but there is no private data currently associated with the object, or the object cannot have private data, JS_GetInstancePrivate also returns NULL.
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See Also
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