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4.2 Conditional Syntax ¶

A conditional in the C preprocessor begins with a conditional directive: ‘#if’, ‘#ifdef’ or ‘#ifndef’.

• Ifdef
• If
• Defined
• Else
• Elif
• __has_attribute
• __has_cpp_attribute
• __has_c_attribute
• __has_builtin
• __has_feature
• __has_extension
• __has_include, __has_include_next
• __has_embed