I was commenting on an answer that thread-local storage is nice and recalled another informative discussion about exceptions where I supposed The only special thing about the execution environment within the throw block is that the exception object is referenced by rethrow. Putting two and two together, wouldn't executing an ...
I have a boost::posix_time::ptime that points to March 31st 2010 like this: ptime p(date(2010, Mar, 31)); I would like to subtract a month (and possibly years) from this date. From the docs I see these two operators: ptime operator-(time_duration) and ptime operator-(days) but none of them can work with months/years. If I try and do...
Hi... The associativity of stream insertion operator is rtl, forgetting this fact sometimes cause to runtime or logical errors. for example: 1st- int F() { static int internal_counter c=0; return ++c; } in the main function: //....here is main() cout<<”1st=”<<F()<<”,2nd=”<<F()<<”,3rd=”<<F(); and the output is: 1st=3,2nd=2,...
Hi, After searching a long time for a performance bug, I read about denormal floating point values. I have an Intel Core 2 Duo and I am compiling with gcc, using "-O2". So what do I do? Can I somehow instruct g++ to avoid denormal values? If not, can I somehow test if a float is denormal? Thanks! Nathan ...
_stuckVertices is an array of pointers and I would like to update one index of that array without using _stuckVertices[ (row * _cols) + column ] 3 times. The reason it is an array of pointers is because the vast majority of the time the pointer will be NULL. The following code works but I need to dereference a each time I use it: void...
I need to retrieve the position of a Gtk::Widget relative to its parent, a Gtk::Table. Most sources (e.g. http://library.gnome.org/devel/gtk-faq/stable/x642.html) say that one needs to call Gtk::Widget::get_allocation(). However, the returned Gtk::Allocation object always contains x = -1, y = -1, width = 1, height = 1. I have to note th...
When creating my own class in Qt I would like my variables in the class to have a standard/default value if I haven't set them to anything. It would be perfect if this was possible to set in the h-file so I don't have to do it in each instance method of my class. You can see what I want to do in the code below. In the example myBool woul...
Hello, I have an arduino with an ethernet shield. I want to know how can i connect it to internet across a firewall proxy. e.g the Arduino Ethernet library have only this reference to demonstrate how to connect your board to internet but no clue how to do it across firewall proxy's etc. Repeated from Arduino help pages. #include <Et...
Hello Is there some C/C++ IDE for windows, which is integrated with LLVM compiler (and clang C/C++ analyzer), just like modern Xcode do. I have Dev-Cpp (it uses outdated gcc) and Code::Blocks (with some gcc). But Gcc gives me very cryptic error messages. I want to get some more user-friendly error messages from clang frontend. Yes, cl...
Hi, I want to find a way to efficiently keep track of a lot of objects at once. One practical example I can think of would be a particle system. How are hundreds of particles kept track of? I think I'm on the right track, I found the term 'instancing' and I also learned about flyweights. Hopefully somebody can shed some light on this and...
I've just bought a new laptop for me on the travel, then on my free time, I've started to test MinGW on it by trying to compile my own OS that is written in C++, then I've created all the files needed and the kernel.cpp: extern "C" void _main(struct multiboot_data* mbd, unsigned int magic); void _main( struct multiboot_data* mbd, unsig...
I happened to find this code return 5. It's OK to write it this way or should definitely be avoid? int& f() { int i = 5; return i; } int main(){ cout<<f()<<endl; } ...
As we know c++ is also an Object Oriented Programming language where most the things are objects like java. So wanted to know is the Serialize and deserializ features are available in c++ as well as we do it in java? If yes how it can be achieved? In java We use Serializable Interface to say that this type of object can be serialized a...
Or if i need to do that, then i should just use shared_ptr? I know i have many questions regarding smart pointer - i still don't quite understand when to use which smart pointer. ...
Where to get streaming (live) video and audio from camera example for Nokia (5800 for ex)? Suppose I want to create some live video streaming service app so I'll have some cool server at the back end. And I know how to do that part. Suppose I have some stand alone app for PCs now I want to go on to mobile devices. So I decided to start ...
Is there a "very bad thing" that can happen &&= and ||= were used as syntactic sugar for bool foo = foo && bar and bool foo = foo || bar? ...
I found this from C++FAQ Generally, No. From a member function or friend of a privately derived class, the relationship to the base class is known, and the upward conversion from PrivatelyDer* to Base* (or PrivatelyDer& to Base&) is safe; no cast is needed or recommended. However users of PrivatelyDer should a...
Hi, I have these 3 file in my program: sample1.h (method in sample1.cpp are defined here) sample1.cpp (all the actual implementations) demo.cpp (I am using the methods in sampe1.cpp here, and have included sample1.h) Now, I am using GDB to debug and I know the basic commands like "break lineno." or "break methodname". But, how do I...
What are the official names for the operators * and & in the context of pointers? They seem to be frequently called dereference operator and address-of operator respectively, but unfortunately, the section on unary operators in the standard does not name them. I really don't want to name & address-of anymore, because & returns a pointer...
I am trying to read a bmp file in C++(Turbo). But i m not able to print binary stream. I want to encode txt file into it and decrypt it. How can i do this. I read that bmp file header is of 54 byte. But how and where should i append txt file in bmp file. ? I know only Turbo C++, so it would be helpfull for me if u provide solution or s...