I thought whitespace effectively did not matter in C. Is this different for the preprocessor? Why do we need to use " \ " when creating multiline macros?
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1 Answers
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Preprocessor directives are terminated by a newline character, so in that context newlines are distinguished from other whitespace.
Newlines are also distinguished inside // comments and string literals. In both cases, line-splicing can be used to extend the lexeme, although it's not considered good style.
Equally, you can extend preprocessor lines using multiline comments, because comments are replaced with a space before preprocessing directives are recognised. That probably would also be discouraged by style guides if they thought of it.
#end**for a#define: it's a one-liner). The \ shows that is continues on the next line. – Weather Vane