What does # stand for in c++ code?

Question

What does the # before s mean in the following snippet? I am not referring to the # before define or the ones used for preprocessor directives.

// Quote a given token stream to turn it into a string.
#define DEV_QUOTED_HELPER(s) #s
#define DEV_QUOTED(s) DEV_QUOTED_HELPER(s)

This question is different from "Stringification - how does it work?" because someone having this question doesn't know the term 'stringification'. It is different from "What is '#' operator in C?" because it appears in C++ code too and in such cases even SO fails to show this question in the list of similar questions(it showed other possible questions in SQL, python etc).

I guess should be tag c and neither c++ not c++11, this is c preprocessor directives — mpromonet, Nov 11 '17 at 10:36
Okay @mpromonet. I had seen this snippet in a primarily c++ codebase. — user3740387, Nov 11 '17 at 10:38

score 5 · Answer 1 · edited Nov 11 '17 at 10:33

5

Taken from https://en.wikipedia.org/wiki/C_preprocessor:

The # operator (known as the "Stringification Operator") converts a token into a string, escaping any quotes or backslashes appropriately.

Example:
#define str(s) #s

str(p = "foo\n";) // outputs "p = \"foo\\n\";"
str(\n)           // outputs "\n"

edited Nov 11 '17 at 10:33

JJJ

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answered Nov 11 '17 at 10:32

OriBS

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What does # stand for in c++ code?

1 Answers1