subprocess.py 文件源码

def wait(self):
            """Wait for child process to terminate.  Returns returncode
            attribute."""
            while self.returncode is None:
                try:
                    pid, sts = _eintr_retry_call(os.waitpid, self.pid, 0)
                except OSError as e:
                    if e.errno != errno.ECHILD:
                        raise
                    # This happens if SIGCLD is set to be ignored or waiting
                    # for child processes has otherwise been disabled for our
                    # process.  This child is dead, we can't get the status.
                    pid = self.pid
                    sts = 0
                # Check the pid and loop as waitpid has been known to return
                # 0 even without WNOHANG in odd situations.  issue14396.
                if pid == self.pid:
                    self._handle_exitstatus(sts)
            return self.returncode