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#if, #elif, #else, #endif
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Directive: #if, #elif, #else, #endif
Syntax: #if test expression
[text-block]
[#elif test expression
text-block]
∙ ∙ ∙
[#else
text-block]
#endif
Summary: Checks each test expression associated with an #if or
#elif directive until a true (nonzero) expression is
found, then processes the <text-block> associated with
that test expression. If there is an #else clause, the
<text-block> associated with it is processed only if no
test expression in the #if or #elif clauses has a nonzero
value.
The test expression can be any expression that evaluates
to a constant, and can contain logical operators and the
"defined" operator. It cannot use the sizeof operator,
type casts, or the float or enum types. The <text-block>
can contain C code or compiler directives.
See also: #define, defined, #ifdef, #ifndef, #undef
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