The difference between exit and return, the difference between exit and return_PHP tutorial

The difference between exit and return, the difference between exit and return

There are several main differences: ​ 1. return returns a function value, which is a keyword; exit is a function. ​ 2. Return is at the language level, which represents the return of the call stack; exit is at the system call level, which represents the end of a process. ​ 3. Return is the exit (return) of the function; exit is the exit of the process. ​ 4. Return is provided by the C language, and exit is provided by the operating system (or given in the function library). ​ 5. return is used to end the execution of a function and transfer the execution information of the function to other calling functions; the exit function is to exit the application, delete the memory space used by the process, and return a status of the application to OS, this status identifies some running information of the application. This information is related to the machine and operating system. Generally, 0 means a normal exit, and non-0 means an abnormal exit. ​ 6. The effect of calling return and exit in non-main function is very obvious, but the phenomenon of calling return and exit in main function is very vague. In most cases, the phenomenon is the same. ​ You can clearly see the difference between vfork and fork: you can try to type the program and experience the specific difference.