{"json_modified": "2016-03-28T08:10:36.264900", "uuid": "be1baba2-0f86-4ca7-8512-8683e0eaa34d", "title": "JS_IsConstructing", "url": "/en-US/docs/Mozilla/Projects/SpiderMonkey/JSAPI_reference/JS_IsConstructing", "tags": ["Obsolete", "SpiderMonkey", "JSAPI Reference"], "translations": [], "modified": "2014-12-19T10:29:54", "label": "JS_IsConstructing", "localization_tags": [], "locale": "en-US", "id": 11042, "last_edit": "2014-12-19T10:29:51", "summary": "<code>JS_IsConstructing</code> must be called only from a <a href=\"/en-US/docs/Mozilla/Projects/SpiderMonkey/JSAPI_reference/JSNative\" title=\"JSNative is the type of many JSAPI callbacks. In particular, APIs such as JS_InitClass and JS_DefineFunctions create custom methods on JavaScript objects that are implemented as JSNative callbacks provided by the application, written in C/C++ code.\"><code>JSNative</code></a> called from the engine. cx and vp must be the arguments that the engine passed to that <code>JSNative</code>.", "sections": [{"id": "Quick_Links", "title": null}, {"id": "Syntax", "title": "Syntax"}, {"id": "Description", "title": "Description"}], "slug": "Mozilla/Projects/SpiderMonkey/JSAPI_reference/JS_IsConstructing", "review_tags": []}