Ch 11. Exception Handling
Introduction
Flags and Return Codes
The stream I/O system does not return an error status flag directly, but rather it yields a value that can be converted into a boolean value that indicates the error:
errono should always be checked after calling any function in which it might be set.
The Assertion Library
The setjmp and longjmp Facility
# include <csetjmp> // include setjmp library ...
When encounter an unrecoverable error, programmer can invoke the longjmp, passing as an argument the jump buffer and a nonzero integer value, rather than tracking back through the sequence of function invocations :
Activation Record Stack
Signals
Exception Types
A class hierarchy in the header file stdexcept in STL
Catch-all exception handler in Java.
C++ permits ellipses to be used as the catch argument.
Rethrowing Exceptions
No finally Clause
class CleanUp { ~CleanUp () { // ... put common clean up code here } }; //... try { CleanUp dummy; //... } catch (IOError & e) { // ... } catch (RunTimeError & e) { // ... } // ... continue with execution
Reference as Exceptions
Exception Class Clonability
class ParseException { public: // constructors ParseException (string & why) : reason(why) { } ParseException (ParseException & why) : reason(why.reason) { } // operators void operator = (ParseException & why)
No Need to Document Exception
Always document a potential exception by placing a throw list in the function header.
Standard Exceptions
void f () throw (string)
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