Boolean in ifdef: is “#ifdef A && B” the same as “#if defined(A) && defined(B)”?

Question

In C++, is this:

#ifdef A && B

the same as:

#if defined(A) && defined(B)

?

I was

Answer 1

Conditional Compilation

You can use the defined operator in the #if directive to use expressions that evaluate to 0 or 1 within a preprocessor line. This saves you from using nested preprocessing directives. The parentheses around the identifier are optional. For example:

#if defined (MAX) && ! defined (MIN)  

Without using the defined operator, you would have to include the following two directives to perform the above example:

#ifdef max 
#ifndef min