Eclipse CDT C++ NULL not resolved

Question

Related: Eclipse CDT "Symbol NULL could not be resolved"

I was under the impression that NULL was a standard macro in C++ and didn't need any headers to be included. Eclipse, on the other hand, thinks it doesn't exist.

Is there some way to remind Eclipse that I'm in C++ mode not C mode for this file, and therefore to shut up about the NULL problem?

possible duplicate of [Why is NULL undeclared?](http://stackoverflow.com/questions/924664/why-is-null-undeclared) — Oliver Charlesworth, Jun 08 '12 at 20:12

score 9 · Accepted Answer · answered Jun 08 '12 at 19:59

9

I was under the impression that NULL was a standard macro in C++.

It is, but it's not part of the language. You still need to include <cstddef> or <cstdlib>, etc.

answered Jun 08 '12 at 19:59

Oliver Charlesworth

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score 3 · Answer 2 · edited Jun 20 '20 at 09:12

Why is NULL undeclared?

Quoted from the top-answer on that question.

NULL is not a built-in constant in the C or C++ languages. In fact, in C++ it's more or less obsolete, just use a plain literal 0 instead, the compiler will do the right thing depending on the context.

Otherwise, add
#include <stddef.h>
to get the NULL definition.

UPDATE: I had the wrong header, corrected now. Thanks! (Quoted from Unwind)

Eclipse CDT C++ NULL not resolved

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