Invoke mysql_waitpid like this:
shell> mysql_waitpid [options] pid wait_time
mysql_waitpid sends signal 0 to the process identified by pid and waits up to wait_time seconds for the process to terminate. pid and wait_time must be positive integers.
If process termination occurs within the wait time or the process does not exist, mysql_waitpid returns 0. Otherwise, it returns 1.
If the kill() system call cannot handle signal 0, mysql_waitpid() uses signal 1 instead.
mysql_waitpid supports the following options:
Display a help message and exit.
Verbose mode. Display a warning if signal 0 could not be used and signal 1 is used instead.
Display version information and exit.
Copyright © 1997, 2016, Oracle and/or its affiliates. All rights reserved.
This documentation is free software; you can redistribute it and/or modify it only under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License.
This documentation is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with the program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA or see http://www.gnu.org/licenses/.