MACROMEDIA FLASH 8-EXTENDING FLASH, Manual

Page: 543 / 554

The C-level API 543
typedef JSBool (*JSNative)(JSContext *cx,
JSObject *obj, unsigned int argc, jsval *argv, jsval
*rval)
Description
Method; describes C-level implementations of JavaScript functions in the following
situations:
■
The
cx
pointer is a pointer to an opaque
JSContext
structure, which must be passed to
some of the functions in the JavaScript API. This variable holds the interpreter’s
execution context.
■
The
obj
pointer is a pointer to the object in whose context the script executes. While the
script is running, the
this
keyword is equal to this object.
■
The
argc
integer is the number of arguments being passed to the function.
■
The
argv
pointer is a pointer to an array of
jsval
structures. The array is
argc
elements
in length.
■
The
rval
pointer is a pointer to a single
jsval
structure. The function’s return value
should be written to
*rval
.
The function returns
JS_TRUE
if successful;
JS_FALSE
otherwise. If the function returns
JS_FALSE
, the current script stops executing and an error message appears.
JSBool JS_DefineFunction()
Usage
JSBool JS_DefineFunction(unsigned short *name, JSNative call, unsigned int
nargs)
Description
Method; registers a C-level function with the JavaScript interpreter in Flash. After the
JS_DefineFunction()
function registers the C-level function that you specify in the
call
argument, you can invoke it in a JavaScript script by referring to it with the name that you
specify in the
name
argument. The
name
argument is case-sensitive.
Typically, this function is called from the
MM_Init()
function, which Flash calls
during startup.