What do these two strange lines of code mean?
thread_guard(thread_guard const&) = delete;
thread_guard& operator=(thread_guard const&) = delete;
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163answers:
2
+10
A:
It is the new C++0x syntax for disabling the certain functions of the class. See wikipedia for an example. Here you are telling that class thread_guard is neither copyable nor assignable.
Naveen
2010-09-13 09:26:59
It works for other functions, too.
sellibitze
2010-10-18 19:53:59
+11
A:
The =delete is a new feature of C++0x. It means the compiler should immediately stop compiling and complain "this function is deleted" once the user use such function (See also: defaulted and deleted functions -- control of defaults of the C++0x FAQ by Bjarne Stroustrup).
The thread_guard(thread_guard const&) is a copy constructor, and thread_guard& operator=(thread_guard const&) is an assignment constructor. These two lines together therefore disables copying of the thread_guard instances.
KennyTM
2010-09-13 09:27:36
Almost. The "use" of a deleted function in an unevaluated context (for example, as expression to `decltype`) can qualify as a template argument deduction failure. This makes a compiler just ignore a template. It doesn't make the compiler stop compiling.
sellibitze
2010-09-13 20:34:20