c++

The C vs. C++ way

Hi, So I have to write a program that will iterate through an image and record the pixel locations corresponding to each color pixel that appears in it. For example, given http://www.socuteurl.com/fishywishykissy I need to find the coordinates of all yellow, purple, dark pink, etc pixels. In C++ I would use a hash table to do this...

Justification for a basic business application in C++?

Aside from "I've already implemented it in C++", and "You must develop it in C++ for it to run on X", what are some good reasons for developing a basic business application in pure C++? ...

Should I use Qt signal/slot mechanisms over traditional callbacks?

A senior developer in my team used traditional C-style callbacks in our Qt application instead of using Qt signal/slot mechanisms. My first reflex would be to replace his code and use Qt signal/slot instead. Is there any good reasons to use callbacks in a Qt application/library? Thanks. ...

Template operator linker error

I have a linker error I've reduced to a simple example. The build output is: debug/main.o: In function main': C:\Users\Dani\Documents\Projects\Test1/main.cpp:5: undefined reference tolog& log::operator<< (char const (&) [6])' collect2: ld returned 1 exit status It looks like the linker ignores the definition in log.cpp....

when I use boost::this_thread::sleep, what happens to its pid directory in /proc/{pid} ?

Hello all, I am having a program which keeps track of other processes whether they are terminated or still running with respect to pid and I do this looking their pid directory in /proc. But when a process goes in sleep, is it like its directory is gone becoz its being my watching process show it as terminated. ...

which is better: a lying copy constructor or a non-standard one?

I have a C++ class that contains a non-copyable handle. The class, however, must have a copy constructor. So, I've implemented one that transfers ownership of the handle to the new object (as below) class Foo { public: Foo() : h_( INVALID_HANDLE_VALUE ) { }; // transfer the handle to the new instance Foo( const Foo&...

How to optimize this simple function which translates input bits into words?

I have written a function which reads an input buffer of bytes and produces an output buffer of words where every word can be either 0x0081 for each ON bit of the input buffer or 0x007F for each OFF bit. The length of the input buffer is given. Both arrays have enough physical place. I also have about 2Kbyte free RAM which I can use for ...

How to set the correct Visual Studio version as JIT debugger?

I have VS2003, VS2005 and VS2008 installed on my machine. The C++ application is compiled with VS2005 but when it crashs and i select debug the Just-In-Time Debugging dialog comes up and only offers me "New instance of Visual Studio .NET 2003". Debugging a 2005 compiled program with 2003 is not possible. If i attach the process to ...

C#.Net Calling a C++ DLL

Hi I got a DLL(without the sourcecode) which exports like this: ?ReceiveCoreDataPtr@@YAXPAX@Z ?xenoAddRigidBodyAngularImpulse@@YAXHMMM@Z ?xenoAddRigidBodyForce@@YAXHMMM@Z ?xenoAddRigidBodyForce@@YAXHMMMMMM@Z ?xenoAddRigidBodyLinearImpulse@@YAXHMMM@Z ?xenoAddRigidBodyPointImpulse@@YAXHMMMMMM@Z ?xenoAddRigidBodyTorque@@YAXHMMM@Z ?xenoCha...

How to update old C code?

I have been working on some 10 year old C code at my job this week, and after implementing a few changes, I went to the boss and asked if he needed anything else done. That's when he dropped the bomb. My next task was to go through the 7000 or so lines and understand more of the code, and to modularize the code somewhat. I asked him how...

Determining CPU usage in WinCE

I want to be able to get the current % CPU usage in a C++ program running under Wince. I found this link that states where the source code is but I cannot find it in my platform builder installation - I expect this is because it isn't the Windows Automotive platform. Does anyone know where I can find this source code or (even better) k...

rvalues and temporary objects in the FCD

It took me quite some time to understand the difference between an rvalue and a temporary object. But now the final committee draft states on page 75: An rvalue [...] is an xvalue, a temporary object or subobject thereof, or a value that is not associated with an object. I can't believe my eyes. This must be an error, right? To ...

SQLite problem with some parameterized queries

I am having some trouble using SQLite and parameterized queries with a few tables. I have noticed some queries using the SELECT * FROM Table WHERE row=? are returning 1 row when there should be more rows returned. If I change the parameterized query to SELECT * FROM Table WHERE row='row' then the correct number of rows is returned. Do...

GCC / C++ Static linking for headers in a shared object

-I am trying to create a shared object libfoo.so. libfoo.so is created from "foo.c" - Assume that I include headers "static.h" and "Dynamic.h" where in I want the compiler to resolve the symbols for Static.h and leave the rest ie from Dynamic.h for runtime. - How do i do this ? What are the CFLAG and LDFLAG options that I need to pas...

Access specifier's and classes and objects?

Alright, im trying to understand this, so a class is simply creating a template for an object. class Bow { int arrows; }; and an object is simply creating a specific item using the class template. Bow::Bow(arrows) { arrows = 20; } also another question, public specifiers are used to make data members avaible in objects and priv...

C++: vector to stringstream

I want to know if it is possible to transform a std::vector to a std::stringstream using generic programming and how can one accomplish such a thing? ...

Struct inside a class

I have a class definition of the form class X { public: //class functions private: A_type *A; //other class variables }; and struct A_type is defined as struct A_type { string s1,s2,s3; }; Inside the constructor, I allocate appropriate memory for A and try A[0].s1="somestring"; It shows segmentation fault. I...

How to "pin" C++/CLI pointers

I am wrapping up a class which reading a custom binary data file and makes the data available to a .net/c# class However a couple of lines down the code, i start getting the memory access violation error which i believe is due to the GC moving memory around, the class is managed Here's the calling code in C# - reader is mixed code ( m...

Declaration for object for which creation is wrapped in macro

The following macro is defined in our code: #define MSGMacro(obj, arg) MyPaymentClass obj(arg) Where MSGMacro is used to creates the object of type MyPaymentClass using code like MSGMacro(Card, 1); MSGMacro(Cash, 2); ---- ---- //removed unwanted things to keep question cleaner. All the above code is in one cpp file, Now the pro...

Clean Eclipse Index, it is out of sync with code

I'm using Eclipse with C++ code via linked resources on Linux. The code analysis index seems to be corrupted (Goto definition lands the cursor close to, but not on, the definition) Refreshing resources doesn't fix it, neither does restarting Eclipse. Is there a way to flush the index and rebuild it? ...