c指向用户定义的对象线程安全的读取？

如果某个值与使用它的某个其他线程同时修改,则只能发生数据争用.标准的主要陈述是：

数据竞争在§1.10/ 21中定义：

The execution of a program contains a data race if it contains two
conflicting actions in different threads,at least one of which is not
atomic,and neither happens before the other.

在§1.10/ 4中定义冲突的地方：

Two expression evaluations conflict if one of them modifies a memory
location (1.7) and the other one accesses or modifies the same memory
location.

因此,您必须在这些读取和任何写入之间使用适当的同步.