Error handling in C

[Tim Conkling <tconkling@...>]

I have a couple of questions regarding error handling of Lua 5 from a 
host application:

How can I go about handling errors that occur in the lua_dofile 
function? If the function fails, it outputs to stderr (which I'd like 
to prevent) and provides no indication that failure has occurred. Is 
there any way I can suppress the output of the error message, discover 
whether an error occurred, and retrieve the error string that would 
normally be written to the console upon failure?

The functions that I expose to my Lua environment from the host app do 
error checking. Currently, if a function is called incorrectly (with 
bad arguments), all I can do is report that an error has occurred -- I 
can't tell which line in which function caused the error. Is there any 
way to get this information?

Thanks,
Tim