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    JS_GetPrivate

    Access the private data field of an object.

    Syntax

    void *
    JS_GetPrivate(JSObject *obj);
    
    Name Type Description
    obj JSObject * An object whose JSClass has the JSCLASS_HAS_PRIVATE flag.

    Description

    JS_GetPrivate accesses an object's private data field. obj must be an instance of a class that has the JSCLASS_HAS_PRIVATE flag.

    New objects' private data fields are initially NULL.

    If obj is a Function object, as reported by JS_ObjectIsFunction, the private data is a pointer to a JSFunction.  (But consider using JS_ValueToFunction instead to access it.)

    Warning: It is dangerous to call JS_GetPrivate on a JSObject * unless the object's JSClass is known. If the object is not of the expected JSClass, the result of JS_GetPrivate would probably be NULL or a pointer to some unexpected type of data. Casting that pointer to the desired type and using it could then cause a crash or worse.

    Getters, setters, and methods of custom classes should use JS_GetInstancePrivate instead to avoid this danger. However, it is safe to use JS_GetPrivate in a finalizer.

    See Also

    Document Tags and Contributors

    Contributors to this page: Sayrer, Sheppy, Dmandelin, Wesgarland, Nickolay, arai, Tservo, Dria, Jorend
    Last updated by: arai,
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