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EXIT(2) System Calls Manual EXIT(2) NAME _exit, wait wait3 - terminate process, wait for child to terminate SYNOPSIS void _exit(status) int status; int wait(status) int *status; int wait((int *)0) #include <sys/vtimes.h> wait3(status, options, ch_vt) int *status; struct vtimes *ch_vt; DESCRIPTION _exit closes all the process's files and notifies the parent process when the parent executes wait. The low-order 8 bits of status are available to the parent process. The call never returns. The function exit(3), which is the normal means of terminating a process, may cause cleanup actions before finally calling _exit. Therefore, _exit should be called to terminate a child process after a fork(2) to avoid flushing buffered output twice. Wait delays until a signal is received or until a child processes ter- minates or receives signal SIGSTOP. There is no delay if any child has died since the last wait, or if there are no extant children. The nor- mal return yields the process id and status of one terminated child. The status of other children may be learned from further wait calls. If status is nonzero, wait sets *status = (s<<8)+t where s is the low 8 bits of status from the child's exit, if any, and t is the termination status of the child. See signal(2) for a list of termination statuses (signals); status 0 indicates normal termination, 0177 a (restartable) process stopped on SIGSTOP. If the 0200 bit of the termination status is set, a core image of the process was produced by the system. Wait3 is similar to wait. An option value of 1 prevents waiting for extant, non-stopped children and causes 0 to be returned if children exist but none have reportable status. If ch_vt is nonzero, resource usage data for the child are reported as by vtimes(2). If the parent process terminates without waiting on its children, they are inherited by process 1 (the initialization process, init(8)). SEE ALSO fork(2), exit(3), signal(2), sh(1) DIAGNOSTICS wait, wait3: ECHILD BUGS If the argument to wait is bogus, the user program gets a memory fault rather than an EFAULT. The 0 third argument to wait3 is a required historical dreg. EXIT(2)