When can you use a character array's name to make a valid L-value?

Question

Given a pointer and an array, setting one equal to another fails in one case, and works in another.

char *c_ptr = "I'm a char pointer";
char c_arry[] = "I'm a char array";
c_ptr = c_arry;  //This line works.
c_arry = c_ptr;  //This line fails.

When the line above fails, it generates this warning: "error: incompatible types when assigning to type". This error seems disingenuous, and frankly, a little slutty, given that just a line prior, she claimed she was my type.

Trying to understand this issue, I re-read K&R's chapter on pointers and arrays and noticed on page 102 their claim that "the array name is the address of the zeroth element". If K&R is accurate, substituting in &c_arry[0] should generate the same error, right? But this line:

&c_arry[0] = c_ptr;

gives me a new error: "lvalue required as left operand of assignment". Why does this so-called identical value generate a different error? When GCC and K&R contradict each another, that's when I turn to the experts on stackoverflow.

Reading up a bit on l-values, I've come to the conclusion that this is an L-value vs. R-value issue, and that c_arry can only be an L-value - that is, an assigned value - in two, and only two situations:

• String initialization (i.e. char c_arry[] = "I'm a char array"; )
• and character assignment (i.e. c_arry[0] = 'A'; )

Is my conclusion accurate? Are these the only two ways that c_arry can ever be assigned?

Or put another way, is there ever an X, for any of the following lines of code, that is ever valid?

c_arry     = X;
&c_arry    = X;
&c_arry[0] = X;
*c_arry    = X;
*c_arry[0] = X;

Answer 1

The fact that "the array name is the address of the zeroth element" is true most of the time¹ does not mean that you can assign it anything. Although this

char str[] = "hello";

looks like an assignment, it is in fact initialization; the concept of lvalue does not apply to it.

Moreover, obtaining an address using & operator never produces an lvalue, so there is no way to come up with an X that does not break your first three examples.

The last two, however, can be assigned, with some minor tweaks:

*c_arry = 'x';           // the same as c_arry[0] = 'x'
char *c_arry_of_ptr[2];
...
*c_arry_of_ptr[0] = 'x';

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¹ One notable exception is sizeof(c_arry) - here, it's not the same as sizeof(&c_arry[0]) for arrays of size other than 1.