Menu
Consider this code snippet:
pid_t cpid = fork(); if (cpid == -1) { perror("fork"); exit(EXIT_FAILURE); } if (cpid == 0) { // in child execvp(argv[1], argv + 1); perror("execvp"); _exit(EXIT_FAILURE); } // in parent How shall I exit the child process if execvp returns? Shall I use exit() or _exit()?
821
In this article Terminates the calling process. The exit function terminates it after cleanup; _exit and _Exit terminate it immediately.
For killing a child process after a given timeout, we can use the timeout command. It runs the command passed to it and kills it with the SIGTERM signal after the given timeout. In case we want to send a different signal like SIGINT to the process, we can use the –signal flag.
You can get the exit status of the child via the first argument of wait() , or the second argument of waitpid() , and then using the macros WIFEXITED and WEXITSTATUS with it. waitpid() will block until the process with the supplied process ID exits.
The exit () function is used to break out of a loop. This function causes an immediate termination of the entire program done by the operation system. void exit (int code); The value of the code is returned to the calling process, which is done by an operation system.
You should definitely use _Exit(). exit() calls the functions you added with atexit() and deletes files created with tmpfile(). Since the parent process is really the one that wants these things done when it exists, you should call _Exit(), which does none of these.
Notice _Exit() with a capital E. _exit(2) is probably not what you want to call directly. exit(3) and _Exit(3) will call this for you. If you don't have _Exit(3), then yes, _exit() is what you wanted.
189
The child of fork() should always call _exit().
Calling exit() instead is a good way to cause pending stdio buffers to be flushed twice.
26
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
