exit和return

Terminate calling process

Terminates the process normally, performing the regular cleanup for terminating programs.

Normal program termination performs the following (in the same order):

• Objects associated with the current thread with thread storage duration are destroyed (C++11 only).
• Objects with static storage duration are destroyed (C++) and functions registered with atexit are called.
• All C streams (open with functions in <cstdio>) are closed (and flushed, if buffered), and all files created with tmpfile are removed.
• Control is returned to the host environment.

Note that objects with automatic storage are not destroyed by calling exit (C++).

If status is zero or EXIT_SUCCESS, a successful termination status is returned to the host environment.
If status is EXIT_FAILURE, an unsuccessful termination status is returned to the host environment.

Otherwise, the status returned depends on the system and library implementation.

exit()和return的区别：

按照ANSI C，在最初调用的main()中使用return和exit()的效果相同。

但要注意这里所说的是“最初调用”。如果main()在一个递归程序中，exit()仍然会终止程序；但return将

控制权移交给递归的前一级，直到最初的那一级，此时return才会终止程序。return和exit()的另一个区别

在于，即使在除main()之外的函数中调用exit()，它也将终止程序。