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Diffstat (limited to 'clang/docs/LanguageExtensions.rst')
| -rw-r--r-- | clang/docs/LanguageExtensions.rst | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/clang/docs/LanguageExtensions.rst b/clang/docs/LanguageExtensions.rst index 5636b8992dc..3ca1010e393 100644 --- a/clang/docs/LanguageExtensions.rst +++ b/clang/docs/LanguageExtensions.rst @@ -164,6 +164,33 @@ The attribute name can also be specified with a preceding and following ``__`` (double underscore) to avoid interference from a macro with the same name. For instance, ``__always_inline__`` can be used instead of ``always_inline``. + +``__has_declspec_attribute`` +---------------------------- + +This function-like macro takes a single identifier argument that is the name of +an attribute implemented as a Microsoft-style ``__declspec`` attribute. It +evaluates to 1 if the attribute is supported by the current compilation target, +or 0 if not. It can be used like this: + +.. code-block:: c++ + + #ifndef __has_declspec_attribute // Optional of course. + #define __has_declspec_attribute(x) 0 // Compatibility with non-clang compilers. + #endif + + ... + #if __has_declspec_attribute(dllexport) + #define DLLEXPORT __declspec(dllexport) + #else + #define DLLEXPORT + #endif + ... + +The attribute name can also be specified with a preceding and following ``__`` +(double underscore) to avoid interference from a macro with the same name. For +instance, ``__dllexport__`` can be used instead of ``dllexport``. + ``__is_identifier`` ------------------- |
