Mysqld process not showing all options on command line in CentOs 7
You shouldn't be relying on the OS processlist to display mysqld options in the events other versions of the OS do not display them (as your questions points out)

What other methods can you use that are OS-independent ???

METHOD #1

If you enabled show_compatibility_56, then login to MySQL and run

SELECT * FROM information_schema.global_variables;


METHOD #2

If you did not enable show_compatibility_56, then login to MySQL and run

SELECT * FROM performance_schema.global_variables;


METHOD #3

From the OS command line, use mysqladmin utility with variables command

mysqladmin -h127.0.0.1 -P3306 --protocol=tcp -uroot -p variables


GIVE IT A TRY !!!