In other examples, nothing was passed by value; everything was passed by reference. bar and foo are BOTH pointers All vars/handles to NON primitive objects in javascript are pointers; pointers ARE native to javascript, they are the default. var bar = function () { alert(“A”); } //bar is a pointer to function1 var foo = … Read more
void (*)() is a type, the type being “pointer to function that takes indeterminate arguments and returns no value”. (void (*)()) is a type-cast to the above type. (void (*)())buf casts buf to the above type. ((void (*)())buf)() calls the function (passing no arguments). In short: It tells the compiler to treat buf as a … Read more
The C++ and C standards leaves a bunch of freedom to compilers. Compilers are free to count to 1 billion between every instruction, or only do so if an integer has a prime value in it. Decent “real” compilers don’t do this. This is a quality of implementation issue. Inlining function objects into something like … Read more
The correct way to do this is: typedef void (*callback_function)(void); // type for conciseness callback_function disconnectFunc; // variable to store function pointer type void D::setDisconnectFunc(callback_function pFunc) { disconnectFunc = pFunc; // store } void D::disconnected() { disconnectFunc(); // call connected = false; }
Like all variables in Kotlin, function references normally cannot be null. In order to allow a null value, you have to add a ? to the end of the type definition, like so: var callback1 : (() -> Unit)? = null var callback2 : (((a) -> c, b) -> Unit)? = null You will usually … Read more
I’m surprised why everybody says it is not possible. It is possible on Linux for non-static functions. I know at least two ways to achieve this. There are GNU functions for backtrace printing: backtrace() and backtrace_symbols() (See man). In your case you don’t need backtrace() as you already have function pointer, you just pass it … Read more
arr //arr arr [] //is an array (so index it) * arr [] //of pointers (so dereference them) (* arr [])() //to functions taking nothing (so call them with ()) void (* arr [])() //returning void so your answer is void (* arr [])() = {}; But naturally, this is a bad practice, just use … Read more
You see, in situations that actually matter from the performance point of view, like calling the function repeatedly many times in a cycle, the performance might not be different at all. This might sound strange to people, who are used to thinking about C code as something executed by an abstract C machine whose “machine … Read more
I haven’t done this in a while! Start with foo and go right. float * (*(*foo())[SIZE][SIZE])() foo is a function with no arguments… Can’t go right since there’s a closing parenthesis. Go left: float * (*(* foo())[SIZE][SIZE])() foo is a function with no arguments returning a pointer Can’t go left further, so let’s cross the … Read more
int (*getFunc())(int, int) { … } That provides the declaration you requested. Additionally, as ola1olsson notes, it would be good to insert void: int (*getFunc(void))(int, int) { … } This says that getFunc may not take any parameters, which can help avoid errors such as somebody inadvertently writing getFunc(x, y) instead of getFunc()(x, y).