JS_LeaveLocalRootScopeWithResult

Obsolete since JavaScript 1.8.5
This feature is obsolete. Although it may still work in some browsers, its use is discouraged since it could be removed at any time. Try to avoid using it.

Leave a local root scope, transferring the result value to the next enclosing root scope.

Syntax

void JS_LeaveLocalRootScopeWithResult(JSContext *cx, jsval rval);
Name Type Description
cx JSContext * Pointer to the context. This must be the same context that was passed to JS_EnterLocalRootScope. Requires request. In a JS_THREADSAFE build, the caller must be in a request on this JSContext.
rval jsval The result value that should remain protected from garbage collection.

Description

See JS_EnterLocalRootScope for an explanation of local root scopes.

The protection this function affords to rval is tenuous. If there is an enclosing local root scope, then rval is transferred to it. Otherwise, the value is stored in an internal per-JSContext slot. This slot is rooted, but the value will eventually be overwritten by some other operation, and it is very difficult to figure out exactly when this will happen—or more to the point, guarantee that it won't happen in the time it takes some specific chunk of code to run.

In any case, all other newborn values protected by the local root scope, aside from rval, become subject to garbage collection.

See Also

MXR ID Search for JS_EnterLocalRootScope

JS_AddRoot, JS_LeaveLocalRootScope, JS_ForgetLocalRoot

Document Tags and Contributors

Contributors to this page: MarkGiffin, tschneidereit, Waldo, Jorend
Last updated by: tschneidereit,