lua_Writer typedef int (*lua_Writer) (lua_State *L, const void* p, size_t sz, void* ud); The type of the writer function used by lua_dump. Every time it produces another piece of chunk, lua_dump calls the writer, passing along the buffer to be written (p), its size (sz), and the data parameter supplied to lua_dump. The writer returns an error code: 0 means no errors; any other value means an error and stops lua

lua_xmove[-?, +?, –] void lua_xmove (lua_State *from, lua_State *to, int n); Exchange values between different threads of the same state. This function pops n values from the stack from, and pushes them onto the stack to.

lua_yield[-?, +?, e] int lua_yield (lua_State *L, int nresults); This function is equivalent to lua_yieldk, but it has no continuation (see §4.7). Therefore, when the thread resumes, it continues the function that called the function calling lua_yield.

lua_yieldk[-?, +?, e] int lua_yieldk (lua_State *L, int nresults, lua_KContext ctx, lua_KFunction k); Yields a coroutine (thread). When a C function calls lua_yieldk, the running coroutine suspends its execution, and the call to lua_resume that started this coroutine returns. The parameter nresults is the number of values from the stack that will be passed as results to lua_resume. When the coroutine is resumed again, Lua calls the given co

math.abs (x) Returns the absolute value of x. (integer/float)

math.acos (x) Returns the arc cosine of x (in radians).

math.asin (x) Returns the arc sine of x (in radians).

math.atan (y [, x]) Returns the arc tangent of y/x (in radians), but uses the signs of both parameters to find the quadrant of the result. (It also handles correctly the case of x being zero.) The default value for x is 1, so that the call math.atan(y) returns the arc tangent of y.

math.ceil (x) Returns the smallest integral value larger than or equal to x.

math.cos (x) Returns the cosine of x (assumed to be in radians).