void

问题 I need to figure out how to pass two different structs to a function. I tried using void * for the parameter but i am receiving the error: warning: dereferencing 'void *' pointer error: request for member left in something not a structure or union same error for member right here is what i did in general terms(code may not compile). struct A{ char *a; struct A *left, *right; } *rootA; struct B{ char *b; struct B *left, *right; } *rootB; void BinaryTree(void *root, void *s){ if(condition) root

问题 This question already has answers here : Should useless type qualifiers on return types be used, for clarity? (6 answers) Closed 4 years ago . I have become somewhat of a const-correctness fanatic when it comes to programming. I've got const's everywhere (where correct of course). Now I've even started const'ing my void return types. You can't create a void object and therefore you can't assign a value to a void object even if it's const or not, which means the "const" becomes redundant. So

问题 This question already has answers here : Should useless type qualifiers on return types be used, for clarity? (6 answers) Closed 4 years ago . I have become somewhat of a const-correctness fanatic when it comes to programming. I've got const's everywhere (where correct of course). Now I've even started const'ing my void return types. You can't create a void object and therefore you can't assign a value to a void object even if it's const or not, which means the "const" becomes redundant. So

问题 I've been trying to use SWIG to wrap around a simple library that uses ioctl() to populate a structure like the following: struct data { header* hdr; void* data; size_t len; }; data is a pointer to a buffer, len is the length of that buffer. I'm unable to figure out how to convert data to a Python string (or array). Furthermore, I need a way to free that buffer in the destructor. Any suggestions are appreciated. 回答1: Since you say "or something else" in the Q's title -- if you choose to use

问题 I've been trying to use SWIG to wrap around a simple library that uses ioctl() to populate a structure like the following: struct data { header* hdr; void* data; size_t len; }; data is a pointer to a buffer, len is the length of that buffer. I'm unable to figure out how to convert data to a Python string (or array). Furthermore, I need a way to free that buffer in the destructor. Any suggestions are appreciated. 回答1: Since you say "or something else" in the Q's title -- if you choose to use

问题 Imagine the following interface in C#: interface IFoo { void Bar(); } How can I implement this in F#? All the examples I've found during 30 minutes of searching online show only examples that have return types which I suppose is more common in a functional style, but something I can't avoid in this instance. Here's what I have so far: type Bar() = interface IFoo with member this.Bar() = void Fails with _FS0010: Unexpected keyword 'void' in expression_. 回答1: The equivalent is unit which is

问题 Say I have a void* named ptr. How exactly should I go about using ptr to store an int? Is it enough to write ptr = (void *)5; If I want to save the number 5? Or do I have to malloc something to save it? 回答1: You're casting 5 to be a void pointer and assigning it to ptr . Now ptr points at the memory address 0x5 If that actually is what you're trying to do .. well, yeah, that works. You ... probably don't want to do that. When you say "store an int" I'm going to guess you mean you want to

问题 I've been looking at a Qt tutorial which uses a construction I haven't seen before: (void) new QShortcut(Qt::Key_Enter, this, SLOT(fire())); (void) new QShortcut(Qt::Key_Return, this, SLOT(fire())); (void) new QShortcut(Qt::CTRL + Qt::Key_Q, this, SLOT(close())); I've tried this without the (void) and it still compiles and works, so what is the purpose of the (void) ? 回答1: Casting an expression to (void) basically tells the compiler to ignore the result of that expression (after computing it)

问题 From what I understand, the keyword void in Javascript is some kind of function that takes one argument and always returns the undefined value. For some reason you need to pass it an argument; it won't work without one. Is there any reason why it requires this argument? What is the point? Why won't it work without an argument. The only use I have seen for it is to produce an undefined result. Are there any other uses for it? If not then it would seem that the requirement for an expression to

问题 Imagine the following code: void DoThis() { if (!isValid) return; DoThat(); } void DoThat() { Console.WriteLine("DoThat()"); } Is it OK to use a return inside a void method? Does it have any performance penalty? Or it would be better to write a code like this: void DoThis() { if (isValid) { DoThat(); } } 回答1: A return in a void method is not bad, is a common practice to invert if statements to reduce nesting. And having less nesting on your methods improves code readability and