This is a follow up to this question, Restricted access for allocated arrays belonging to separate object, after discovering that returning by value across compilation units doesn't help to hint th...

Suppose I have a function which takes some pointer parameters - some non-const, through which it may write, and some const through which it only reads. Example: void f(int * a, int const *b); Supp...

I have function that receives an array of pointers like so: void foo(int *ptrs[], int num, int size) { /* The body is an example only */ for (int i = 0; i < size; ++i) { for (int j = 0; j ...

g++ does implement __restrict__ for pointers, but I could not find anything about iterators. My overall intent is to encourage the compiler to vectorize stl loops. Edit: Even if the compiler is una...

I was working on highly "vectorizable" code and noted that regarding the C++ __restrict keyword/extension ~, Clang's behavior is different and impractical compared to GCC even in a simple...

In unsafe code, is it correct to have several mutable references (not pointers) to the same array, as long as they are not used to write to the same indices? Context I would like to yield several...

Quote from C99 standard: 6.5.2.3 5 One special guarantee is made in order to simplify the use of unions: if a union contains several structures that share a common initial sequence (see below), an...

I'm using Beej's Guide to Networking and came across an aliasing issue. He proposes a function to return either the IPv4 or IPv6 address of a particular struct: 1 void *get_in_addr( struct sockadd...

I have gone through some queries on the similar topic and some material related to it. But my query is mainly to understand the warning for the below code. I do not want a fix !! I understand there...

If dot_product is declared as float dot_product(const float* restrict a, const float* restrict b, unsigned n); would calling it with dot_product(x, x, x_len) be "undefined", according to the...

Consider this hypothetical implementation of vector: template<class T> // ignore the allocator struct vector { typedef T* iterator; typedef const T* const_iterator; template<class It&...

I understand that having a const method in C++ means that an object is read-only through that method, but that it may still change otherwise. However, this code apparently changes an object throug...

Please consider the following code: typedef struct { int type; } object_t; typedef struct { object_t object; int age; } person_t; int age(object_t *object) { if (object->type == PERSON) {...

Having recently read that the main reason why fortran is faster than c/c++ in numerical computations is because there is no pointer aliasing. Apparently, using restrict or __restrict__ keywords al...

Does the following code invoke undefined behavior (due to aliasing violation or otherwise)? int foo(int (*a)[10], int (*b)[5]) { (*a)[5]++; return (*b)[0]; } int x[10]; foo(&x, (int (*)[5])...

std::vector<int> a; a.push_back(1); a.push_back(a[0]); I just learned that the code above can be very dangerous. (If it's not obvious why, you're not alone... it wasn't obvious to me either....

I've got some code that I've been using successfully for some years to implement a "variant-type object"; that is, a C++ object that can hold a values of various types, but only uses (approximately...