Why do we have pointers other than void
Type safety. Defining the type of pointers helps the compiler find errors where you are trying to use data of the wrong type through a pointer. That’s the reason C has types in the first place.
pointers
Pointer expressions: **ptr++, *++*ptr and ++**ptr use
Remember array name can easily decays into pointer to first element in most expressions (read some exceptions where array name not decaying into a pointer to first element? ably answered by @H2CO3). For better understanding, consider my diagrams: First, suppose a stored in memory as follows. a +—-+—-+—-+—-+—+ | 0 | 1 | 2 | … Read more
Pointer-to-pointer dynamic two-dimensional array
The first method cannot be used to create dynamic 2D arrays because by doing: int *board[4]; you essentially allocated an array of 4 pointers to int on stack. Therefore, if you now populate each of these 4 pointers with a dynamic array: for (int i = 0; i < 4; ++i) { board[i] = new … Read more
Why can’t I cast a function pointer to (void *)?
You can’t fix the warning. In fact, in my opinion it should be a hard error since it’s illegal to cast function pointers to other pointers because there are architectures out there today where this isn’t just a violation of the C standard but an actual error that will make the code not work. Compilers … Read more
How to know if a pointer points to the heap or the stack?
There is no way of doing this – and if you need to do it, there is something wrong with your design. There is a discussion of why you can’t do this in More Effective C++.
const usage with pointers in C
const char* is, as you said, a pointer to a char, where you can’t change the value of the char (at least not through the pointer (without casting the constness away)). char* const is a pointer to a char, where you can change the char, but you can’t make the pointer point to a different … Read more
Meaning of complex C syntax [duplicate]
c is an array of 10 function pointers that return a char* and take a int** as an argument. (*c[10]) ^^^^ = array of 10 (*c[10]) ^ = function pointer So right now we have an array of 10 function pointers. char *(*c[10]) ^^^^^^ = returns a char* char *(*c[10])(int** p) ^^^^^ = takes a … Read more
Are these compatible function types in C?
These two defect reports address your issue: Defect Report #316 Defect Report #317 Defect report 316 says (emphasis mine going forward): The rules for compatibility of function types in 6.7.5.3#15 do not define when a function type is “specified by a function definition that contains a (possibly empty) identifier list”, […] and it has a … Read more
Rationale behind the container_of macro in linux/list.h
It adds some type checking. With your version, this compiles fine (without warning): struct foo { int bar; }; …. float a; struct foo *var = container_of(&a, foo, bar); With the kernel version, the compiler reports: warning: initialization from incompatible pointer type Good explanation of how the macro works: container_of by Greg Kroah-Hartman.
Why are all of my “this” pointers the same value?
As noted in comments, you’re seeing the this pointer for a temporary and then copying the temporary into the vector. Since the temporary is temporary your system is reusing the same memory location on each loop iteration. However, if you print the this pointer for the vector elements, you will notice they are placed in … Read more