C++ function declaration followed by throw of of must see

Problem description:

Why is C++ sometimes followed by the throw() keyword in function declarations?

Explanation:

The keyword throw(something) is added after the C++ function to limit the exception security of this function. This is an exception specification that only occurs when a function is declared, indicating that the function may throw any type of exception.

throw void fun () ();           // means that the fun function is not allowed to throw any exceptions, which means that the fun function is exception safe.

void fun () throw (...). ;       // means that the fun function can throw any kind of exception.

void fun () throw (exceptionType);       // means that the fun function can only throw exceptions of type exceptionType.

Examples:

void GetTag () throw (int);                                         // means that only int type exceptions are thrown
void GetTag() throw(int, char);               // throws an in, char type exception
throw void GetTag () ();                                       // means that no type exception will be thrown
void GetTag () throw (...). ;                             // Means that any type of exception is thrown

void GetTag () throw (int); Means that only int type exception is thrown, which does not mean that 1 will definitely throw an exception, but 1 will only throw an exception of int type. If a non-int type exception is thrown, unexsetpion() function is called to exit the program.

throw void GetTag () ();   if you add an throw() attribute to your function that never throws an exception, the compiler will be very smart about the intent of the code and how to optimize it.