RE: customizable Lua "panic" behavior

["Joshua Jensen" <jjensen@...>]

> | This is the only solution I've actually liked thus far.  It 
> is easy to 
> | envision something like:
> | 
> | void RunMain()
> | {
> |         // All app code that would've been in main() goes here.
> | }
> | 
> | static int StartExecution(lua_State *L)
> | {
> |    RunMain();
> |    return 0;
> | }
> | 
> | int main()
> | {
> |     lua_pushcfunction(L, StartExecution);
> |     lua_call(0,0);
> | }
> |
> Do you remove the exit call with this? or are you saying it 
> will never be called? I can understand trapping exceptions, 
> but if an exception occurs, your Lua mem really may be 
> totally hosed. Calling lua_close() would have unpredictable 
> results. Maybe i'm not following you here...

Based on what Edgar said and what I understand about Lua, exit()
shouldn't get called.  luaD_breakrun() is the only place exit() can get
called.

void luaD_breakrun (lua_State *L, int errcode) {
  if (L->errorJmp) {
    L->errorJmp->status = errcode;
    longjmp(L->errorJmp->b, 1);
  }
  else {
    if (errcode != LUA_ERRMEM)
      message(L, l_s("unable to recover; exiting\n"));
    exit(EXIT_FAILURE);
  }
}

lua_call() calls luaD_runprotected() which immediately sets up the
L->errorJmp.  That being the case, it appears to me that exit() will
never be called in the middle of a lua_call(), thereby making a pretty
slick Lua "exception" handler.

Josh