More effective C + + clause 9 use destructor to avoid leaking resources

1. "When the function throws an exception, the execution of the current function is paused, and the matching catch statement begins to be found." First check whether the throw itself is inside the try block, and if so, check the catch statement associated with the try block to see if one of them matches the object being thrown. If a matching catch is found, the exception is handled, and if it is not found, it exits the current function (frees the current function's memory and revokes the local object) and continues to look in the calling function. ("C + + Primier") This is called stack unwinding.

2. Once an exception is thrown during the execution of the function, the execution of the next statement is stopped, the executing of the TRY block (the statement after the throw within the try block is no longer executed) and the search for a matching catch statement is made, and the local object that has been created is properly revoked during the step out of the try block. Runs a destructor for the local object and frees up memory.

3. If the memory is requested in the heap before throw, and the statement that frees the memory happens after the throw statement, the statement will not perform a memory leak if an exception is thrown.

4. The workaround is to encapsulate the pointer type in a class and free memory in the destructor for that class. This way, even if an exception is thrown, the destructor of the class will run and the memory can be disposed appropriately. The C + + standard library provides a class template called Auto_ptr, which is used to accomplish this function.

More effective C + + clause 9 use destructor to avoid leaking resources