& *

[Lanarcam]

I couldn't find a response in the archives.

Is the following instruction defined by the C language?

int i;

int k = & * i;

 

[Maarten]

I couldn't find a response in the archives.

Is the following instruction defined by the C language?

int i;

int k = & * i;

Have you tried it? What does it even mean?

Maarten

main.c: In function ‘main’:
main.c:6:15: error: invalid type argument of unary ‘*’ (have ‘int’)

 

[BartC]

I couldn't find a response in the archives.

Is the following instruction defined by the C language?

int i;

int k = & * i;

& and * are complementary, in that they tend to cancel each other out (one
creates a pointer to something, one dereferences a pointer).

But, while &*A and *&A do cancel out, the compiler will likely first check
that *A and &A are legal before considering the & or * .

So you example &*i probably won't work, because *i doesn't make sense. But
it might work as *&i, because &i is legal.

 

[James Kuyper]

I couldn't find a response in the archives.

Is the following instruction defined by the C language?

int i;

int k = & * i;

As I indicated in my message a few hours ago, while 6.5.2p3 means that &
and * cancel each other out, it also says "except that the constraints
on the operators still apply". For the '*' operator, there is a
constraint that "The operand of the unary * operator shall have pointer
type." (6.5.2p2). 'i' doesn't have a pointer type, so the above code is
a constraint violation - the C standard does not define its behavior.

 

[88888 Dihedral]

Bartæ–¼ 2012å¹´4月3日星期二UTC+8上åˆ5時16分27秒寫é“：

& and * are complementary, in that they tend to cancel each other out (one
creates a pointer to something, one dereferences a pointer).

But, while &*A and *&A do cancel out, the compiler will likely first check
that *A and &A are legal before considering the & or * .

So you example &*i probably won't work, because *i doesn't make sense. But
it might work as *&i, because &i is legal.

int j;
int* p; // int* a avaiable that can hold and address
p=&j ;// p holds j's address=&j