We have a PHP web app running on a customer's machine. For an update, we have a bit of code in C that we'd like to include as a native opaque library along with the PHP web app. How does one go about calling a C/C++ lib. function from PHP? It cannot be assumed that the PHP app, called by the web server, has any sort of permission to c...
Hey all, I was wondering how one can fix an upper limit for the length of a string (in C++) for a given platform. I scrutinized a lot of libraries, and most of them define it arbitrarily. The GNU C++ STL (the one with experimental C++0x features) has quite a definition: size_t npos = size_t(-1); /*!< The maximum value that can be stor...
In C# or Java, classes are declared and defined at the same time. In C++, the norm is to do that separately. What if we write the whole class in one , say .cpp, file and include that in files that references to it, what kinds of bad thing technically would happen besides a lengthened compilation process? ...
OLE Variants, as used by older versions of Visual Basic and pervasively in COM Automation, can store lots of different types: basic types like integers and floats, more complicated types like strings and arrays, and all the way up to IDispatch implementations and pointers in the form of ByRef variants. Variants are also weakly typed: th...
What is PocoCapsule current status? Is it evolving? Has it been forked with some other product? What is about the whole idea of IoC for C++? If PocoCapsule is not evolving, is it because IoC was considered not useful for C++, unsafe, other patterns appeared or something else? As far as I understand there are 2-3, maybe few more products...
How awful is it - or is it perfectly acceptable - to index a loop on an enumeration? I have an enumeration defined. The values of the literals are default values. The assigned values do not have any significance, will not have any significance, and the values of any literals added in the future will also not have any significance. It's ...
I have some legacy code I want to port to C#. I cannot modify the C++ code, I just have to make do with what I'm given. So, the situation. I'm using SwIG, and I came across this function: void MarshalMe(int iNum, FooClass** ioFooClassArray); If I ran SWIG over this, it wouldn't know what to do with the array, so it will create a SWIG...
I have a DLL which contains a class with static members. I use __declspec(dllexport) in order to make use of this class's methods. But when I link it to another project and try to compile it, I get "unresolved external symbol" errors for the static data. e.g. In DLL, Test.h class __declspec(dllexport) Test{ protected: static int d;...
Why does the following give no compilation error?: // T.h template<class T> class X { public: void foo(int a = 42); }; // Main.cpp #include "T.h" #include <iostream> template<class T> void X<T>::foo(int a = 13) { std::cout << a << std::endl; } int main() { X<int> x; x.foo(); // prints 42 } It seems as thoug...
Hi, Assume that we have multiple arrays of integers. You can consider each array as a level. We try to find a sequence of elements, exactly one element from each array, and proceed to the next array with the same predicate. For example, we have v1, v2, v3 as the arrays: v1 | v2 | v3 ----------------- 1 | 4 | 16 2 | 5 | 81 3 ...
I have need for a function pointer that takes two arguments and returns a string. I would like to pass an adapter that wraps a function that takes one argument, and returns the string (i.e. discard one of the arguments). I can trivially build my own adapter, that takes the 2 arguments, calls the wrapped function passing just the one ar...
Hello everybody, I've got a question concerning nasm and its linkage to C++. I declare a litte test function as extern "C" void __cdecl myTest( byte i1, byte i2, int stride, int *width ); and I call it like this: byte i1 = 1, i2 = 2; int stride = 3, width = 4; myTest( i1, i2, stride, &width ); the method only serves to debug assembl...
I have declared: queue<int, list<int> > Q After a series of calls: Q.push(37); Q.pop(); Q.push(19); Q.push(3); Q.push(13); Q.front(); Q.push(22); Q.push(8); Q.back(); I get: 19->3->13->22->8->NULL What I don't get is what the calls to Q.front() and Q.back() do. From what I understand, they return a reference to the first or la...
I'm reading a registry value like this: char mydata[2048]; DWORD dataLength = sizeof(mydata); DWORD dwType = REG_SZ; ..... open key, etc ReqQueryValueEx(hKey, keyName, 0, &dwType, (BYTE*)mydata, &dataLength); My problem is, that after this, mydata content looks like: [63, 00, 3A, 00, 5C, 00...], i.e. this looks like a unicode?!?!. I...
It says that if there is a virtual function, it is a good practice to have a virtual destructor. However, if the object is created on the stack but not on heap, do we still need to do that? Regards, ...
A preprocessor definition that includes defined(X) will never evaluate to true, but (defined X) will. This occurs in MSVC9; I have not tested other preprocessors. A simple example: #define FEATURE0 1 #define FEATURE1 0 #define FEATURE2 1 #define FEATURE3 (FEATURE0 && !FEATURE1 && (defined(FEATURE2))) #define FEATURE4 (FEATURE0 && !FEAT...
I was working on a program in Netbeans on Linux using a gcc compiler when, upon switching to Visual C++ on Windows 7, the code failed to compile as Visual C++ says it expected constant expression on several lines. On Netbeans, I simply did something similar to char name[fullName.size()];, while on Visual C++, I tried, among other things,...
The ListView control of Windows Explorer gives a highlight to whatever item is under the mouse, without affecting the current selection. This helps enormously with relating what item a given tooltip applies to within a listview - especially in report mode. However, I am currently unable to find any APIs that would give my MFC applicati...
Why is it that if you open up an EXE in a hex editor, you will see all sorts of things. If computers only understand binary then shouldn't there only be 2 possible symbols seen in the file? Thanks ...
Hello, I'm trying to replicate a template I've used before with a member function, and it isn't going very well. The basic form of the function is template<class T> T Convert( HRESULT (*Foo)(T*)) { T temp; Foo(&temp); //Throw if HRESULT is a failure return temp; } HRESULT Converter(UINT* val) { *val = 1; return S_...