 arg1);
	js_pushnumber(J, arg2);
	js_pcall(J, 2);
	js_pop(J, 1);
}
</pre>

<h2>Complete userdata example</h2>

<pre>
#include &lt;stdio.h&gt;
#include &lt;mujs.h&gt;

#define TAG "File"

static void new_File(js_State *J)
{
	FILE *file;

	if (js_isundefined(J, 1)) {
		file = stdin;
	} else {
		const char *filename = js_tostring(J, 1);
		file = fopen(filename, "r");
		if (!file)
			js_error(J, "cannot open file: '%s'", filename);
	}

	js_currentfunction(J);
	js_getproperty(J, -1, "prototype");
	js_newuserdata