casting

问题 Is it okay to cast function location with void pointer though function pointers size is not always the same as opaque pointer size? I already did search about opaque pointers , and casting function pointers . I found out function pointers and normal pointers are not the same on some systems. void (*fptr)(void) = (void *) 0x00000009; // is that legal??? I feel I should do this void (*fptr)(void)= void(*)(void) 0x00000009; It did work fine , though I expected some errors or at least warnings I

问题 So, I have rather esoteric question. I'm trying to create a somewhat generic, but typed property collection system. It's reliant on a core assumption that seems to be erroneous. The code illustrates the issue: import java.lang.Integer; public class Test { private static Object mObj = new String("This should print"); public static void main(String[] args ) { String s = Test.<String>get(); System.out.println(s); try { // actual ClassCastException reported HERE int i = Test.<Integer>get(); }

问题 I know that (Int) -> Void can't be typecasted to (Any) -> Void : let intHandler: (Int) -> Void = { i in print(i) } var anyHandler: (Any) -> Void = intHandler <<<< ERROR This gives: error: cannot convert value of type '(Int) -> Void' to specified type '(Any) -> Void' Question : But I don't know why this work? let intResolver: ((Int) -> Void) -> Void = { f in f(5) } let stringResolver: ((String) -> Void) -> Void = { f in f("wth") } var anyResolver: ((Any) -> Void) -> Void = intResolver I messed

问题 Within the following code, $quiz_object->personalities contains an array of Personality objects. // Loop through each personality that exists for the quiz foreach($quiz_object->personalities AS $existing_personality) { // Show all of the existing personalities echo $existing_personality->GetQuizMakerPersonalityHTML(); } How do I "cast" (I think that's the right word) my variable $existing_personality within the foreach loop as the object type? I wish to do this so that when I type $existing

问题 Is there a way to convert unsigned char array to float array without dereferencing each element of uchar array? unsigned char* arr1 = malloc(sizeof(unsigned char) * 3); float* arr2 = malloc(sizeof(float) * 3); *arr1 = 3; *(arr1 + 1) = 55; *(arr1 + 2) = 213; *arr2 = (float)(*arr1); // 3.0 *(arr2 + 1) = (float)(*(arr1 + 1)); // 55.0 *(arr2 + 2) = (float)(*(arr1 + 2)); // 213.0 来源： https://stackoverflow.com/questions/62136164/c-convert-unsigned-char-array-to-float-array

问题 Is there a way to convert unsigned char array to float array without dereferencing each element of uchar array? unsigned char* arr1 = malloc(sizeof(unsigned char) * 3); float* arr2 = malloc(sizeof(float) * 3); *arr1 = 3; *(arr1 + 1) = 55; *(arr1 + 2) = 213; *arr2 = (float)(*arr1); // 3.0 *(arr2 + 1) = (float)(*(arr1 + 1)); // 55.0 *(arr2 + 2) = (float)(*(arr1 + 2)); // 213.0 来源： https://stackoverflow.com/questions/62136164/c-convert-unsigned-char-array-to-float-array

问题 Say, something like this: int SayHelloThenReturnTen(void) { puts("Hello world"); return 10; } Then later: ((void(*)(void))SayHelloThenReturnTen)(); Is that safe? Is it safe to "trash" the return value by casting to a void pointer? Is this safe and cross platform, or is this undefined behavior ? 回答1: Is that safe? It is safe to cast a function pointer to any function pointer type. Casting the result back to the original type will yield a pointer value equal to the the original pointer. It is

问题 I integrated Google cast to my Android app. All my content is playing via service with notification. When I play media using Google cast it add own notification. Is it possible to disable default google cast notification and use only own notification? Thank you. 回答1: This is great portal, you ask some question, than you answer own qustion by yourself :) To disable cast notification needed just to pass null while for setNotificationOptions() in class CastOptionsProvider. Complete answer:

问题 I integrated Google cast to my Android app. All my content is playing via service with notification. When I play media using Google cast it add own notification. Is it possible to disable default google cast notification and use only own notification? Thank you. 回答1: This is great portal, you ask some question, than you answer own qustion by yourself :) To disable cast notification needed just to pass null while for setNotificationOptions() in class CastOptionsProvider. Complete answer:

问题 I integrated Google cast to my Android app. All my content is playing via service with notification. When I play media using Google cast it add own notification. Is it possible to disable default google cast notification and use only own notification? Thank you. 回答1: This is great portal, you ask some question, than you answer own qustion by yourself :) To disable cast notification needed just to pass null while for setNotificationOptions() in class CastOptionsProvider. Complete answer: