UPDATE: There is a new class called QGraphicsSceneMouseEvent that makes this a little easier. I just finished an example using it here: https://stackoverflow.com/a/26903599/999943 It differs with the answer below in that it subclasses QGraphicsScene, not QGraphicsView, and it uses mouseEvent->scenePos() so there isn’t a need to manually map coordinates. You are on the right track, … Read more
You might want to overload operator ++ for your enum if you really want to iterate its values: Foo& operator++( Foo& f ) { using UT = std::underlying_type< Foo >::type; f = static_cast< Foo >( static_cast< UT >( f ) + 1 ); return f; } and use for (Foo foo = Foo::First; foo <= … Read more
I ran into this exact same issue, but with Visual Studio Community Edition 2019. The solution was to download the Windows 10 SDK using the Visual Studio installer. Once I did that the next compile worked fine. The header file “crtdbg.h” is part of the Windows 10 SDK kit. I believe you will find crtdbg.h … Read more
This is a solution I found when looking for an answer previously. It stated that you should always avoid using system() because: It is resource heavy It defeats security — you don’t know you it’s a valid command or does the same thing on every system, you could even start up programs you didn’t intend … Read more
Function pointers themselves can’t have default values. You’ll either have to wrap the call via the function pointer in a function that does have default parameters (this could even be a small class that wraps the function pointer and has an operator() with default paremeters), or have different function pointers for the different overloads of … Read more
How about letting OS do it for you: long long int getFolderSize(string path) { // command to be executed std::string cmd(“du -sb “); cmd.append(path); cmd.append(” | cut -f1 2>&1″); // execute above command and get the output FILE *stream = popen(cmd.c_str(), “r”); if (stream) { const int max_size = 256; char readbuf[max_size]; if (fgets(readbuf, max_size, … Read more
There’s a good example on how to set up a minimal service on MSDN. See the parts about writing the main function, entry point and also the example code. Once you’ve got a windows service built and running, you’ll discover the next major gotcha: it’s a pain to debug. There’s no terminal (and hence no … Read more
should std::common_type use std::decay? Yes, see Library Working Group Defect #2141. Short version (long version, see link above): declval<A>() returns a A&& common_type is specified via declval, n3337: template <class T, class U> struct common_type<T, U> { typedef decltype(true ? declval<T>() : declval<U>()) type; }; common_type<int, int>::type therefore yields int&&, which is unexpected proposed resolution … Read more
Your code is being accepted without any warnings because the original C++11 restriction is considered a defect in the standard, which allows implementations to fix the behavior. See CWG DR975, DR1048 and N3638. 975. Restrictions on return type deduction for lambdas [Moved to DR status at the April, 2013 meeting as part of paper N3638.] … Read more
Try using gluLookAt glClearColor(0.0, 0.0, 0.0, 1.0); glClear(GL_COLOR_BUFFER_BIT); glMatrixMode(GL_PROJECTION); glLoadIdentity(); /* use this length so that camera is 1 unit away from origin */ double dist = sqrt(1 / 3.0); gluLookAt(dist, dist, dist, /* position of camera */ 0.0, 0.0, 0.0, /* where camera is pointing at */ 0.0, 1.0, 0.0); /* which direction is … Read more