Error messages from C

[Daniel Silverstone <dsilvers@...>]

I recently wanted to create an error message in C.
Rather than mess about in C concatenating bits of strings, I decided
to push the strings onto the stack, lua_concat() them, and then
call lua_error(L, lua_tostring(L, -1)).

Is that:
	(a) Safe?
	(b) The most efficient way?

Many thanks in advance.

Daniel