Handling errors of modules

["Nodir Temirhodzhaev" <tnodir@...>]

Hello!
After error some modules return nil and error message.
In my module i want to save the error code in lua_State
(or errno?) and return nil. And needed global function
to get this error code. To get error message module
must have another function.
Eg., module.strerror( errcode() )

Also i want compare this code from another.
Eg., if errcode() == module.err.nomem then ...

Where is store this code: errno, lua_State->errorJmp.status
or add new member to lua_State (int errcode)?

Thanks.
Sorry for my english