#elif directive — Else-if for conditional compilation
#elif constant-expression
The #elif
directive marks a
region of conditional compilation. Every #elif
must be paired with an introductory
directive: #if
, #ifdef
, or #ifndef
. If the initial condition was false
(0
), and every subsequent #elif
condition is false, and
constant-expression
is true (nonzero),
subsequent statements are compiled until the next #elif
, #else
, or #endif
directive is reached for this level
of nesting.