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

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C++ includ开发者_开发技巧e and import difference

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

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• #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 #.

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#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.

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

See these topics:

• #import Directive (C/C++)
• #include Directive (C/C++)