WAIT(II) 2/9/75 WAIT(II) NAME wait - wait for process to terminate SYNOPSIS (wait = 7.) sys wait (process ID in r0) (status in r1) wait(status) int *status; DESCRIPTION Wait causes its caller to delay until one of its child processes terminates. If any child has died since the last wait, return is immediate; if there are no children, return is immediate with the error bit set (resp. with a value of -1 returned). The normal return yields the process ID of the terminated child (in r0). In the case of several children several wait calls are needed to learn of all the deaths. If no error is indicated on return, the r1 high byte (resp. the high byte stored into status ) contains the low byte of the child process r0 (resp. the argument of exit ) when it terminated. The r1 (resp. status ) low byte contains the termination status of the process. See signal (II) for a list of termination statuses (signals); 0 status indicates normal termination. A special status (0177) is returned for a stopped process which has not terminated and can be restarted. See ptrace (II). If the 0200 bit of the termination status is set, a core image of the process was produced by the system. If the parent process terminates without waiting on its children, the initialization process (process ID = 1) inherits the children. SEE ALSO exit (II), fork (II), signal (II) DIAGNOSTICS The error bit (c-bit) is set if there are no children not previously waited for. From C, a returned value of -1 indicates an error.