How can I get the current RTX ticks?

I don't need to change it, I only need the ticks number so I can calculate the time for some operation such as

start = os_ticks_get();
do something here
end = os_ticks_get();

then end - start is the time.

I need to find out the API for os_ticks_get()

I don't need to change it, I only need the ticks number so I can calculate the time for some operation such as

start = os_ticks_get();
do something here
end = os_ticks_get();

then end - start is the time.

I need to find out the API for os_ticks_get()

in rt_time.h....

extern U16 os_time;