What is the difference between #import and #include in C++?

Question

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C++ include and import difference

Can someone explain the difference and where may I use one versus the other?

Possible duplicate http://stackoverflow.com/questions/172262/c-include-and-import-difference — DumbCoder, Mar 14 '11 at 15:55
the first does not exists, the second performs copy-pasting of the file given to it. — Alexandre C., Mar 14 '11 at 15:57

Didier Trosset · Answer 1 · 2021-08-15T14:09:14.173

6

#include includes a file in the current compilation unit.
#import does not exist in the C++ standard.

This answer was true in '14. However, the C++ standard has evolved since then and import now exists. Without the #.

edited Aug 15 '21 at 14:09

answered Mar 14 '11 at 15:56

Didier Trosset

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Bad answer, wrongly upvoted. import DOES exist in C++20 – Ariel M. Aug 13 '21 at 20:50
Don't want to nitpick, but `#import` still does not exist in the C++20 standard. Only `import` does. Thanks anyway, I've added a note to my answer. – Didier Trosset Aug 15 '21 at 14:15

Nawaz · Answer 2 · 2011-03-14T16:00:41.760

4

#import imports information (types, functions, variables etc) from .lib file. It's non-standard directive.
#include includes header file.

See these topics:

edited Mar 14 '11 at 16:00

answered Mar 14 '11 at 15:55

Nawaz

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score 4 · Answer 3 · answered Mar 14 '11 at 15:55

#include cause the referenced file to be "copy-and-pasted" at the current position during the preprocessing phase.

#import is not in the C++ standard, but is an extension provided by some compiler. There is no consensus about what it does. For GCC, it is equivalent to #include but try to ensure that the file has not already been included. For MSVC, it may have another meaning.

It is best to avoid #import (sadly) if you want to write code portable to multiple compilers.

What is the difference between #import and #include in C++?

3 Answers3