Jan 11, 2014 · 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.

May 14, 2024 · Whenever the child exits or stops, the parent is sent a SIGCHLD signal. The parent can use the system call wait () or waitpid () along with the macros WIFEXITED and WEXITSTATUS with it to learn about the status of its stopped child.

Mar 4, 2014 · You need to use waitpid(3) or wait(1) in the parent code to wait for the child to exit and get the error message. The syntax is: pid_t waitpid(pid_t pid, int *status, int options); or pid_t wait(int *status); status contains the exit status. Look at the man pages to see you how to parse it.

Feb 22, 2019 · Your processes have exited normally. <defunct> means the process is dead and the only thing that's left is its PID and its exit status. To clean up these <defunct> entries in the process table, the parent process must either wait() for its children or exit itself.

Almost solved: when the top-level process bash gets SIGTERM -- it exists, but tail -f continues to run. How do I instruct tail -f to exit when the parent process exits? E.g. it should also get the signal. Note: Can't use bash traps since exec on the last line replaces the process completely.

The process's parent is sent a SIGCHLD signal. The value status & 0xFF is returned to the parent process as the process's exit status, and can be collected by the parent using one of the wait (2) family of calls. The function _Exit () is equivalent to _exit ().

When the child process terminates ("dies"), either normally by calling exit, or abnormally due to a fatal exception or signal (e.g., SIGTERM, SIGINT, SIGKILL), an exit status is returned to the operating system and a SIGCHLD signal is sent to the parent process.

You have the child call _exit () to avoid flushing stdio (or other) buffers when the child process exits. Since the child process constitutes an exact copy of the parent process, the child process still has whatever the parent had in "stdout" or "stderr", the buffers from <stdio.h>.

Ends the current process and makes an exit status value for the process available to the system. The argument status specifies a return status for the process that is ending. Ending the process has the following results: _exit () closes all open file …

May 11, 2019 · You can use either _exit or exit, but you shouldn't use return. When you fork a child, you retain the entire call stack as part of forking the child. So if you use return, you end up returning up all the way through your program, potentially continuing on and performing other tasks, which is almost certainly not what you want.