c11

Suppose we have a function declaration for which we do not have access to its definition: void f(int * restrict p, int * restrict q, int * restrict r); Since we do not know how the pointers will be accessed, we cannot know if a call will trigger undefined behavior or not -- even if we are passing the same pointer, like the example at 6.7.3.1.10 explains: The function parameter declarations: void h(int n, int * restrict p, int * restrict q, int * restrict r) { int i; for (i = 0; i < n; i++) p[i] = q[i] + r[i]; } illustrate how an unmodified object can be aliased through two restricted pointers.

This question already has answers here : What is size_t in C? (12 answers) Closed 4 years ago . First of all, what do I mean, by 'correct definition`? For example, K&R in "C Programming Language" 2nd ed. , in section 2.2 Data Types and Sizes , make very clear statements about integers: There are short , int and long for integer types. They are needed to repesent values of different boundaries. int is a "naturally" sized number for a specific hardware, so also probably the most fastest. Sizes for integer types short , int and long are purely implementation-dependent. But they have restrictions.

I was trying to learn how to use the "new" C11 Generic expressions but I ran into a wall. Consider the following code: #include <stdlib.h> #include <stdio.h> #define test(X, Y, c) \ _Generic((X), \ double: _Generic((Y), \ double * : test_double, \ default: test_double \ ), \ int: _Generic((Y), \ int * : test_int, \ default: test_int \ ) \ ) (X, Y, c) int test_double(double a, double *b, int c); int test_int(int a, int *b, int c); int test_double(double a, double *b, int c) { return 1; } int test_int(int a, int *b, int c) { return 2; } int main() { double *t = malloc(sizeof(double)); int *s =

This question already has answers here : Closed 2 years ago . Why doesn't C provide struct comparison? (5 answers) The unavailability of structs as comparison operands is one of the more obvious things in C that don't make too much sense (to me). structs can be passed by value and copied via assignments but == is not specified for them. Below are the relevant parts of the C11 standard (draft) that define the constraints of the equality operators ( == and != ) and the simple assignment operator ( = ). Note the lack of structures and unions in the constraints of equality operators. (Apart from

Working in C11, the following struct: struct S { unsigned a : 4; _Bool b : 1; }; Gets layed out by GCC as an unsigned (4 bytes) of which 4 bits are used, followed by a _Bool (4 bytes) of which 1 bit is used, for a total size of 8 bytes. Note that C99 and C11 specifically permit _Bool as a bit-field member. The C11 standard (and probably C99 too) also states under §6.7.2.1 'Structure and union specifiers' ¶11 that: An implementation may allocate any addressable storage unit large enough to hold a bit-field. If enough space remains, a bit-field that immediately follows another bit-field in a