Hi all, is there a way to hide columns of a buffer (text file, you know what I mean) while editing it in Vim? e.g. text visible in the buffer before hiding column 2&3: abbcccccc accdddddd And after hiding them: acccccc adddddd (Not to mention I'm working with really huge files (sometimes over 200 gb).) And yeah, I had found fold...
Can anyone explain why the following code does not compile (on g++ (GCC) 3.2.3 20030502 (Red Hat Linux 3.2.3-49))? struct X { public: enum State { A, B, C }; X(State s) {} }; int main() { X(X::A); } The message I get is: jjj.cpp: In function 'int main()': jjj.cpp:10: 'X X::A' is not a static member of 'struct X' jjj.cpp:10...
say I have a class: class A { public: A() {} }; and a function: void x(const A & s) {} and I do: x(A()); could someone please explain to me the rules regarding passing temporary objects by reference? In terms of what the compiler allows, where you need const, if an implicit copy happens, etc. From playing around, it seems like...
After reading this article on Herb Sutter's blog, I experimented a bit and ran into something that puzzles me. I am using Visual C++ 2005, but I would be surprised if this was implementation dependent. Here is my code: #include <iostream> using namespace std; struct Base { //Base() {} ~Base() { cout << "~Base()" << endl; } };...
Why is the Visual C++ compiler calling the wrong overload here? I am have a subclass of ostream that I use to define a buffer for formatting. Sometimes I want to create a temporary and immediately insert a string into it with the usual << operator like this: M2Stream() << "the string"; Unfortunately, the program calls the operator<<(...
I have a process in an MS Acess database that the users will usually run once daily, but could be more or less. It takes several minutes and requires temporary exclusive access because it deletes and recreates the main table. I have code to check to see if there are other users in the db before the process starts, but is there a way to c...
While debugging crash in a multithreaded application I finally located the problem in this statement: CSingleLock(&m_criticalSection, TRUE); Notice that it is creating an unnamed object of CSingleLock class and hence the critical section object gets unlocked immediately after this statement. This is obviously not what the coder wanted...
Hello, My question (which will follow after this, sorry about the long intro, the question is down there in bold) is originally inspired by Item 23 in Herb Sutters Exceptional C++ where we find something like this: <snip> ... int main() { GenericTableAlgorithm a( "Customer", MyWorker() ); a.Process(); } with class GenericT...
I'm creating a logger with the following sections: // #define LOG(x) // for release mode #define LOG(x) log(x) log(const string& str); log(const ostream& str); With the idea to do: LOG("Test"); LOG(string("Testing") + " 123"); stringstream s; LOG(s << "Testing" << 1 << "two" << 3); This all works as intended, but when I do: LOG(s...
Why is it not allowed to get non-const reference to a temporary object, which function getx() returns? Clearly, this is prohibited by C++ Standard but I am interested in the purpose of such restriction, not a reference to the standard. struct X { X& ref() { return *this; } }; X getx() { return X();} void g(X & x) {} int f(...
Is it possible to change the temporary object and to pass it as an argument? struct Foo { Foo& ref() { return *this; } Foo& operator--() { /*do something*/; return *this; } // another members }; Foo getfoo() { return Foo(); } // return Foo() for example or something else void func_val(Foo x) {} void func_ref(const Foo & x) ...
For a client I need to temporarily route their traffic to my own subdomain. Their host (a shared host) needs to be reconfigured for the site to work, but the client wants their site online ASAP (what else is new ;-) Considering the following: It's a new site/new domain, so there is no legacy SEO traffic. Preferably I'ld like the c...
I have been coding in C++ for the last 6 years. But there is one question that I have not been able to figure out. I want to ask, are all temporaries in C++, rvalues? If no, can anyone provide me an example where temporary produced in the code is an lvalue? ...
Suppose I want to pass a temporary object into a function. Is there a way to do that in 1 line of code vs. 2, with a struct? With a class, I can do: class_func(TestClass(5, 7)); given: class TestClass { private: int a; short b; public: TestClass(int a_a, short a_b) : a(a_a), b(a_b) { } int A() const ...
Is there a way to call a method on a temporary declared object without being forced to assign 1st the object to a variable? See below: class Test { private $i = 7; public function get() {return $this->i;} } $temp = new Test(); echo $temp->get(); //ok echo new Test()->get(); //invalid syntax echo {new Test()}->get(); //...
Years ago I believed that C was absolutely pure compared to C++ because the compiler couldn't generate any code that you couldn't predict. I now believe counter examples include the volatile keyword and memory barriers (in multiprocessor programming or device drivers for memory-mapped hardware devices, where plain assembly language woul...
Hi, I've got a std::vector which I need to sort by selected algorithms for certain operations, but to maintain its original state (e.g. items ordered by when they were entered) the rest of the time. Obviously I can use std::copy to create a temporary vector and sort that, but I'm wondering if there's a better way, possibly by timestamp...
Hi, is the following code safe (it works in DEBUG) : void takesPointer(const Type* v);//this function does read from v, it doesn't alter v in any way Type getValue(); ... takesPointer(&getValue());//gives warning while compiling "not an lvalue" ... Type tmp = getValue(); takesPointer(&tmp);//this is safe, and maybe I should just do it, ...
Consider the following code: std::string my_error_string = "Some error message"; // ... throw std::runtime_error(std::string("Error: ") + my_error_string); The string passed to runtime_error is a temporary returned by string's operator+. Suppose this exception is handled something like: catch (const std::runtime_error& e) { st...
Consider the following function: void f(const char* str); Suppose I want to generate a string using stringstream and pass it to this function. If I want to do it in one statement, I might try: f((std::ostringstream() << "Value: " << 5).str().c_str()); // error This gives an error: 'str()' is not a member of 'basic_ostream'. OK, s...