Linux's stddef.h defines offsetof() as: #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER) whereas the Wikipedia article on offsetof() (http://en.wikipedia.org/wiki/Offsetof) defines it as: #define offsetof(st, m) \ ((size_t) ( (char *)&((st *)(0))->m - (char *)0 )) Why subtract (char *)0 in the Wikipedia version? I...
Incase of pointer arithmetic, are the integers automatically converted to their signed variants? If yes, why? Suppose I do int *pointer; int *pointerdiff; unsigned int uiVal = -1; pointerdiff = pointer + uiVal // Pointer will contain valid address here. where pointer is a pointer to int and uiVal is initialized to -1, then I find...
In the many search functions of C (bsearch comes to mind) if a result is found, a pointer to the spot in the array is returned. How can I convert this pointer to the index in the array that was searched (using pointer arithmetic, i assume). ...
#include<stdio.h> main() { int a[]={0,2,4,6,8}; int *ptr; ptr=a; printf("%d", *((char*)ptr+4)); } *((char*)ptr+4)) What is the purpose of this? ...
Hi everybody, I'm having trouble understanding the behavior of the MS VC compiler on this one. This line compiles fine, but the result I get is not what I'd expect at all: this->Test((char *)&CS2 - (char *)&CS1 == sizeof(void *)); The CS1 and CS2 arguments are declared as follows: myFunction(tCS1* CS1, tCS2* CS2) {... tCS1 and tCS2...
title explains all and why i cant perform this operation var data:pbyte; x:int64; o:pointer; begin o:=data+x; end; thanks in advance regards ...
If I do *ptr[x], is that equivalent to *(ptr[x]), or (*ptr)[x]? ...
Careless use of templates can cause bloat. One way to avoid that bloat is to have a thin typesafe template that wraps non-typesafe non-template code. To do this, the wrapper needs to provide some way for the non-template code to access things it knows nothing about. For example, in a data structure, the wrapper defines the node structs....
I want to take some fields from packet struct using pointer arithmetic.But what is wrong with the code below ? In first condition i think if i go 4 byte(2 short field) from beginning of packet i get tLow .But it does not give expected value.Additionally second case i want to get data field by going 12 byte from beginning of packet .What ...