Some summary of member variable declaration parameters in "objective-c" memory management

1 "Set method memory management related parameters

Retain//release old value, retain new value (for OC pair image type)

Assign//Direct Assignment (default parameter, for non-OC objects)

Copy//release old value, copy new value

2 "whether to generate setter or Getter method

ReadWrite//Generate setter and Getter methods at the same time

ReadOnly//Generate Getter method only

3 "Multithreading Management

Nonatomic//High performance

Atomic//Low performance

Some summary of member variable declaration parameters in "objective-c" memory management