thread safety semantic classification

Leading I - description applies per-instance.

Leading C - description applies across all instances of the class

OTO - One Thread Only. The thread that owns the object is the only one that may use it.

OTT - One Thread At A Time. Any thread may use the object, but only one at a time. Use some kind of mutual exclusion mechanism to allow multiple threads to safely access the same object.

GRP - Group. It's complex, in that different groups of members have different access rules, and context dictates whether some particular useage is allowed when other threads are already using the object.

R/W - Reader/Writer. A special (and common) case of GRP. One writer may access the object, or multiple readers may access the object.

FT - Free Threaded. Anything goes.