luasocket/src/except.h

#ifndef EXCEPT_H
#define EXCEPT_H
/*=========================================================================*\
* Exception control
* LuaSocket toolkit (but completely independent from other modules)
*
* This provides support for simple exceptions in Lua. During the
* development of the HTTP/FTP/SMTP support, it became aparent that
* error checking was taking a substantial amount of the coding. These
* function greatly simplify the task of checking errors.
*
* The main idea is that functions should return nil as its first return
* value when it finds an error, and return an error message (or value)
* following nil. In case of success, as long as the first value is not nil,
* the other values don't matter.
*
* The idea is to nest function calls with the "try" function. This function
* checks the first value, and calls "error" on the second if the first is
* nil. Otherwise, it returns all values it received. 
*
* The protect function returns a new function that behaves exactly like the
* function it receives, but the new function doesn't throw exceptions: it
* returns nil followed by the error message instead.
*
* With these two function, it's easy to write functions that throw
* exceptions on error, but that don't interrupt the user script. 
\*=========================================================================*/

#include "lua.h"

int except_open(lua_State *L);

#endif