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| #if defined(_LIBCPP_VERSION) && STDEXEC_CLANG() | ||
| # define STDEXEC_NAMESPACE_STD_BEGIN \ | ||
| STDEXEC_PRAGMA(GCC diagnostic push) \ | ||
| STDEXEC_PRAGMA(GCC diagnostic ignored "-Wpragma-clang-attribute") \ |
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Why are we suppressing GCC warnings in a block guarded by STDEXEC_CLANG()? And why are we not using STDEXEC_PRAGMA_PUSH(), STDEXEC_PRAGMA_POP() and STDEXEC_PRAGMA_IGNORE_GNU("-Wpragma-clang-attribute")?
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Why are we suppressing GCC warnings in a block guarded by
STDEXEC_CLANG()?
No particular reason, I suppose. I'll change it.
And why are we not using
STDEXEC_PRAGMA_PUSH(),STDEXEC_PRAGMA_POP()andSTDEXEC_PRAGMA_IGNORE_GNU("-Wpragma-clang-attribute")?
That's answered in the final two lines of the comment before the definition:
// This uses STDEXEC_PRAGMA directly rather than STDEXEC_PRAGMA_PUSH() and friends
// because those are defined further down, after the first use of these macros below.Did you miss that, or find it not compelling?
When building stdexec with Clang and libc++ version 23+, `-Wpragma-clang-attribute` causes many errors that look like this: ``` error: unused attribute '__visibility__' in '#pragma clang attribute push' region [-Werror,-Wpragma-clang-attribute] ``` attributable to uses of the `STDEXEC_NAMESPACE_STD_BEGIN` macro. stdexec only uses that macro to forward-declare non-functions, and the attribute is only applicable to functions, so the warning fires on every region where stdexec forward-declares things in `std`. This diff addresses the problem by modifying the `STDEXEC_NAMESPACE_STD_BEGIN`/`_END` macros to push and pop a `-Wno-pragma-clang-attribute` setting around the region whenever building with Clang and libc++. GCC also fails when building with libc++ version 23+, but the failure is because GCC doesn't recognize the `#pragma clang attribute push` pragma and so fails with an unsuppressable warning-as-error; the tip of `main` in libc++ resolves this problem by only emitting the pragma when compiling with Clang.
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/ok to test 3711250 |
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/ok to test e9d7af3 |
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When building stdexec with Clang and libc++ version 23+,
-Wpragma-clang-attributecauses many errors that look like this:attributable to uses of the
STDEXEC_NAMESPACE_STD_BEGINmacro. stdexec only uses that macro to forward-declare non-functions, and the attribute is only applicable to functions, so the warning fires on every region where stdexec forward-declares things instd.This diff addresses the problem by modifying the
STDEXEC_NAMESPACE_STD_BEGIN/_ENDmacros to push and pop a-Wno-pragma-clang-attributesetting around the region whenever building with Clang and libc++. GCC also fails when building with libc++ version 23+, but the failure is because GCC doesn't recognize the#pragma clang attribute pushpragma and so fails with an unsuppressable warning-as-error; the tip ofmainin libc++ resolves this problem by only emitting the pragma when compiling with Clang.