fgets noit version - ctypes works but its weird. copy paste this to scratchpad with environment set to browser

_example-cTypes-fgets.js

Cu.import("resource://gre/modules/ctypes.jsm");
var libc = ctypes.open("msvcrt.dll");


var struct_FILE = new ctypes.StructType("FILE"); //set to var only so can run multiple times in scratchpad, can change back to const
var fopen = libc.declare("fopen", // symbol name
	ctypes.default_abi, // cdecl calling convention
	struct_FILE.ptr, // return type (FILE*)
	ctypes.char.ptr, // first arg (const char*)
	ctypes.char.ptr); // second arg (const char*)

var fgetc = libc.declare("fgetc", // symbol name
	ctypes.default_abi, // cdecl calling convention
	ctypes.int.ptr, // return type (FILE*)
	struct_FILE.ptr); // second arg (const char*)

var fgets = libc.declare("fgets", // symbol name
	ctypes.default_abi, // cdecl calling convention
	ctypes.jschar.ptr, // return char pointer
	ctypes.jschar.ptr, // first arg char pointer
	ctypes.int, //second arg int
	struct_FILE.ptr); // third arg FILE pointer

var myfile = fopen("C:\\Users\\3K2KYC1\\Desktop\\FirefoxPortable\\newfile.in", "r");
//Services.wm.getMostRecentWindow(null).alert(myfile);



var line = new ctypes.jschar;
var ret = fgets(line.address(), 2, myfile);

Services.wm.getMostRecentWindow(null).alert(line);
Services.wm.getMostRecentWindow(null).alert(ret);

//newfile.in already exists and its contents is "ABC" no quotes
//using size 2 as 2nd arg on line 30
//line - is set to "ctypes.jschar("A")" no quotes, which is the first char in the file, but i said get 2 char why didnt it give first 2 chars if try 3 it gives something weird 
//ret - is set to "ctypes.jschar.ptr(ctypes.UInt64("0xfba2b32"))"

//if use size of 3:
//line - "ctypes.jschar("\u4241")"
//ret - "ctypes.jschar.ptr(ctypes.UInt64("0x8fefce8"))"

Rev2

I learned on MSDN if it has * next to name it means it's a pointer so fixed the code above. Also changed FILE to struct_FILE, as good practice you dont set itself to .ptr I'm thinking, it just makes sense.