=proto
duk_context *duk_get_context(duk_context *ctx, int index);

=stack
[ ... val! ... ]

=summary
<p>Get a context pointer for a Duktape thread at <code>index</code>.  If the
value at <code>index</code> is not a Duktape thread or the index is invalid,
returns <code>NULL</code>.</p>

<p>The returned context pointer is only valid while the Duktape thread
is reachable from a garbage collection point of view.</p>

<p>If you prefer an error to be thrown for an invalid value or index,
use <code><a href="#duk_require_context">duk_require_context()</a></code>.</p>

=example
duk_context *new_ctx;

/* Create a new thread and get a context pointer. */

(void) duk_push_thread(ctx);
new_ctx = duk_get_context(ctx, -1);

/* You can use new_ctx as long as the related thread is reachable
 * from a garbage collection point of view.
 */

duk_push_string(new_ctx, "foo");

/* This duk_pop() makes the new thread unreachable (assuming there
 * is no other reference to it), so new_ctx is no longer valid
 * afterwards.
 */

duk_pop(ctx);

/* Using new_ctx here may cause a crash. */

=tags
stack