Use a condition variable. You wait on the condition variable or 5 minutes passing. Remember to check for spurious wakeups. cppreference I cannot find a good stack overflow post on how to use a condition variable in a minute or two of google searching. The tricky part is realizing that the wait can wake up … Read more
N2543 is the proposal, and it has a detailed discussion about size(). The choice between Option 3 [not providing size()] and Option 2 [providing a O(1) size()] is more a matter of judgment. I have chosen Option 3 for the same reason that I chose insert-after instead of insert-before: Option 3 is more consistent with … Read more
The maximal number of binary digits of a N-decimal value is the ceil value of (N * log(10) / log(2)). A single decimal digit needs ceil(3.32) binary digits, That is 4. For sizes of 8 bits it is: Decimals = ceil(8 * Size / 3.32) = ceil(2.41 * Size). For the sign (overhead and allocation) … Read more
The primary use of noexcept is for generic algorithms, e.g., when resizing a std::vector<T>: for an efficient algorithm moving elements it is necessary to know ahead of time that none of the moves will throw. If moving elements might throw, elements need to be copied instead. Using the noexcept(expr) operator the library implementation can determine … Read more
The hard part of writing this custom clock is figuring out how to write its now() function. In the example below I base the now() off of system_clock‘s now(). First I do some detective work to discover that my system_clock has an epoch of New Years 1970, neglecting leap seconds. This is known as unix … Read more
This is done in order to make sure that connection object outlives the asynchronous operation: as long as the lambda is alive (i.e. the async. operation is in progress), the connection instance is alive as well.
Yes, this is valid, there was defect report 1688: Volatile constexpr variables that was filed for this, saying: There does not appear to be language in the current wording stating that constexpr cannot be applied to a variable of volatile-qualified type. Also, the wording in 5.19 [expr.const] paragraph 2 referring to “a non-volatile object defined … Read more
You can use std::is_same<T,U>::value from C++11 onwards. Here, T, and U are the types, and value will be true if they are equivalent, and false if they are not. Note that this is evaluated at compile time. See http://en.cppreference.com/w/cpp/types/is_same
But now that has me thinking — did I do this correctly? Yes you did. Is there a better way in C++11 or C++14 to tell the compiler that I want it to immediately invoke a lambda I’ve written? Not that I know of. A lambda is also just a function object, so you need … Read more
It’s not desirable in the general case. (Note that it’s quite easy for std::function<T(A)> to specify what e.g. argument_type is: it’s just A! It’s available in the type definition.) It would be possible to require each and every function object type to specify its argument types, and in turn mandate that the closure types generated … Read more