git: cd2a65a60701 - stable/13 - sys/cdefs.h: add __noexcept and __noexcept_if

The branch stable/13 has been updated by dim:

URL: https://cgit.FreeBSD.org/src/commit/?id=cd2a65a60701d806e8ebbf97b6c77c880e0c9746

commit cd2a65a60701d806e8ebbf97b6c77c880e0c9746
Author:     Lexi Winter <ivy@FreeBSD.org>
AuthorDate: 2024-02-02 16:41:40 +0000
Commit:     Dimitry Andric <dim@FreeBSD.org>
CommitDate: 2025-12-29 23:46:45 +0000

    sys/cdefs.h: add __noexcept and __noexcept_if
    
    These macros provide the C++11 noexcept and noexcept(...) keywords if
    we're compiling in a C++11 environment.  Otherwise, they expand to an
    empty string.
    
    This will be used to add the required noexcept specifier to several libc
    functions as required in C++11.
    
    MFC after:      2 weeks
    
    Reviewed by: imp
    Pull Request: https://github.com/freebsd/freebsd-src/pull/1085
    
    (cherry picked from commit 02b0d4b688cc4deb14cb6e7534a2a4958e48b753)
---
 sys/sys/cdefs.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/sys/sys/cdefs.h b/sys/sys/cdefs.h
index 8fd07ce85a05..96a3742c4a1d 100644
--- a/sys/sys/cdefs.h
+++ b/sys/sys/cdefs.h
@@ -394,6 +394,17 @@
 #endif
 #endif
 
+/*
+ * noexcept keyword added in C++11.
+ */
+#if defined(__cplusplus) && __cplusplus >= 201103L
+#define __noexcept noexcept
+#define __noexcept_if(__c) noexcept(__c)
+#else
+#define __noexcept
+#define __noexcept_if(__c)
+#endif
+
 /*
  * nodiscard attribute added in C++17 and C23, but supported by both LLVM and
  * GCC in earlier language versions, so we use __has_c{,pp}_attribute to test