29 ms·

While he's technically right, you have no guarantee that the value as a whole is written unless you use the proper fences or synchronize it in some way.

• iainmerrick 7y ago
  “While he's technically right, you have no guarantee” Well, is he technically right or not? It sounds like you think he is not right.
  • rocqua 7y ago
    He's right on assembly level of assignment, but the compiler is free to emit assembly that will tear. Some compilers might do that for optimization purposes.
    • Sharlin 7y ago
      The (C or C++) compiler is free to do anything because reading and writing a non-`atomic` variable from two different threads without synchronization is undefined behavior.
  • vvanders 7y ago
    He's right that the value will be moved atomically, however the compiler is free to reorder the store/load of fences are omitted.