ABL electronic PIC Microcontrollers PIC16 - Manual (Page 142)

Any processed
section
can contain further conditional clauses, nested to any
depth. Each nested
#else
,
#elif
, or
#endif
directive belongs to the closest pre-
ceding
#if
directive.
The net result of the preceding scenario is that only one code
section
(possibly
empty) will be compiled.
Directives
#ifdef
and
#ifndef
You can use the
#ifdef
and
#ifndef
directives anywhere
#if
can be used. The
#ifdef
and
#ifndef
conditional directives let you test whether an identifier is
currently defined or not. The line
#ifdef identifier
has exactly the same effect as
#if 1
if
identifier
is currently defined, and the
same effect as
#if 0
if
identifier
is currently undefined. The other directive,
#ifndef
, tests true for the “not-defined” condition, producing the opposite
results.
The syntax thereafter follows that of the
#if
,
#elif
,
#else
, and
#endif
.
An identifier defined as NULL is considered to be defined.
mikroC - C Compiler for Microchip PIC microcontrollers
mikroC
making it simple...
134
MikroElektronika: Development tools - Books - Compilers
page