if(p)

[Doug Gwyn <gwyn>]

>     Section 9.3 Conditional statement:
> 	if ( expression ) statement
> 	if ( expression ) statement else statement
>     In both cases the expression is evaluated and if it is non-zero,
                                                    ^^^^^^^^^^^^^^^^^
This implies a comparison against 0.  Therefore if "expression" is a
pointer, this is comparison of a pointer with 0, which is the special
case previously discussed.  There is no concept of "evaluates to zero"
independently of "comparison with zero".

>     the first substatement is executed.  In the second case the second
>     substatement is executed if the expression is 0.

Don't take K&R too much as gospel.  It is an excellent book,
but it really did not try to specify everything to the level
that a language lawyer would want.  (X3J11 is trying to do that.)
K&R has to be read with the attitude of extracting the "spirit"
of the language from what is implied as well as from what is said.