User Guide

The C-level API 361
Arguments
JSObject *obj
• Typically, this argument is passed in and converted using the JS_ValueToObject() function.
Returns
A pointer to a null-terminated string. The caller should not free this string when it finishes.
JSObject *JS_NewArrayObject()
Description
This function creates a new object that contains an array of JSVals.
Arguments
JSContext *cx
, unsigned int length, jsval *v
• The cx argument is the opaque JSContext pointer that passes to the JavaScript function.
• The length argument is the number of elements that the array can hold.
• The v argument is an optional pointer to the jsvals to be stored in the array. If the return
value is not
null, v is an array that contains length elements. If the return value is null,
the initial content of the array object is undefined and can be set using the
JS_SetElement() function.
Returns
A pointer to a new array object or the value null upon failure.
long JS_GetArrayLength()
Description
Given a pointer to an array object, this function gets the number of elements in the array.
Arguments
JSContext *cx
, JSObject *obj
• The cx argument is the opaque JSContext pointer that passes to the JavaScript function.
• The obj argument is a pointer to an array object.
Returns
The number of elements in the array or -1 upon failure.