luaL_verror

[Dirk Zoller <Dirk.Zoller@...>]

Hello,

I noticed a misunderstanding in the definition of the luaL_verror
function.
In ANSI-C there are two kinds of printf like functions: those for
immediate use accept a variable number of parameters via ellipses "...",
while those for building other printf-like functions accept a va_list
type which is a disguised pointer to the args passed as ... to a calling
function. The second kind taking va_list instead of ... is customarily
named vsometingf.

At least lua_verror is misnamed as it takes ... and not va_list it
should be named lua_errorf.

That aside, it is not possible to build other printf-like functions on
top of lua_verror. You cannot pass the ellipes on to a called function
as ellipses but only as va_list.

I'd suggest a change as follows:

void luaL_verrorf (lua_State *lua_state, char const *fmt, va_list argp)
{
  char buff[500];
  vsprintf(buff, fmt, argp);
  lua_error(L,buff);
}

void luaL_errorf (lua_State *lua_state,char const *fmt, ...)
{
  va_list argp;
  va_start(argp, fmt);
  luaL_verror (buff, fmt, argp);
  va_end(argp);
}

(I'm using the "multistate" variant of Lua which replaces the global
variable lua_state by a parameter to each function.)

With only a few more lines we'd have both flavours and could use
luaL_verrorf() to build more fancy error handlers. One might want to
avoid
breaking old code by

#define luaL_verror luaL_errorf


Regards

-- 
Dirk Zoller <Dirk.Zoller@rhein-main.netsurf.de>