WEXITSTATUS( status ) returns the exit status of the child. WIFEXITED( status ) returns true if the child terminated normally, that is, by calling exit(3) or _exit(2), or by returning from main().

Inspected with the following macros (which take the integer itself as an argument, not a pointer to it, as is done in wait() and If status is not NULL, wait() and waitpid() store status information in the int to which it points. Status for traced children which have stopped is provided even if thisĪlso return if a stopped child has been resumed by delivery of SIGCONT. Return immediately if no child has exited.Īlso return if a child has stopped (but not traced via ptrace(2)). The value of options is an OR of zero or more of the following constants: Meaning wait for the child whose process ID is equal to the value of pid. Waitpid() waits only for terminated children, but this behavior is modifiable via the options argument, as described below. Waitpid(-1, &status, 0) The waitpid() system call suspends execution of the calling process until a child specified by pid argument has changed state. Wait() and waitpid() The wait() system call suspends execution of the calling process until one of its children terminates.

This page, a child whose state has changed and which has not yet been waited upon by one of these system calls is termed waitable. Interrupts the call (assuming that system calls are not automatically restarted using the SA_RESTART flag of sigaction(2)). Otherwise they block until either a child changes state or a signal handler If a child has already changed state, then these calls return immediately. Remains in a 'zombie' state (see NOTES below). Terminated child, performing a wait allows the system to release the resources associated with the child if a wait is not performed, then the terminated child A state change is considered to be: the child terminated the child was stopped by a signal or the child was resumed by a signal. || /* Since glibc 2.12: */ _POSIX_C_SOURCE >= 200809LĪll of these system calls are used to wait for state changes in a child of the calling process, and obtain information about the child whose state hasĬhanged. _SVID_SOURCE || _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE & _XOPEN_SOURCE_EXTENDED Int waitid(idtype_t idtype, id_t id, siginfo_t * infop, int options ) įeature Test Macro Requirements for glibc (see feature_test_macros(7)): Pid_t waitpid(pid_t pid, int * status, int options )

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