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244 - 09: Handling Exceptions on E: EDivByZero do begin Result := 0; ShowMessage (E.Message); end; end; end; In the exception-handling statement, we catch the EDivByZero exception, which is defined by the run-time library. There are a number of these exception types referring to run-time problems (such as a division by zero or a wrong dynamic cast), to system problems (such as out-of-memory errors), or to component errors (such as a wrong index). All of these exceptions classes inherit from the base class Exception , which offers some minimal features like the Message property I used in the code above. These classes form an actual hierarchy with some logical structure. note Notice that while types in Object Pascal are generally marked with an initial letter T, exception classes take an exception to the rule and generally start with the letter E. The Exceptions Hierarchy Here is a partial list of the core RTL exception classes defined in the SysUtils unit (most of the other system libraries add their own exception types): Exception EArgumentException EArgumentOutOfRangeException EArgumentNilException EPathTooLongException ENotSupportedException EDirectoryNotFoundException EFileNotFoundException EPathNotFoundException EListError EInvalidOpException ENoConstructException EAbort EHeapException EOutOfMemory EInvalidPointer EInOutError EExternal EExternalException EIntError EDivByZero ERangeError EIntOverflow EMathError Marco Cantù, Object Pascal Handbook
