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[libc++] Fix missing 'get_new_handler()' for Windows builds #150182

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[libc++] Fix missing 'get_new_handler()' for Windows builds #150182

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e04029e
fix missing 'get_new_handler()' for Windows builds
siradam7th Jul 23, 2025
c4ae877
remove 'FIXME' and 'XFAIL' for 'get_new_handler()' test
siradam7th Jul 23, 2025
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4 changes: 0 additions & 4 deletions libcxx/include/__new/new_handler.h
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Original file line number Diff line number Diff line change
Expand Up @@ -15,14 +15,10 @@
# pragma GCC system_header
#endif

#if defined(_LIBCPP_ABI_VCRUNTIME)
# include <new.h>
#else
_LIBCPP_BEGIN_UNVERSIONED_NAMESPACE_STD
typedef void (*new_handler)();
_LIBCPP_EXPORTED_FROM_ABI new_handler set_new_handler(new_handler) _NOEXCEPT;
_LIBCPP_EXPORTED_FROM_ABI new_handler get_new_handler() _NOEXCEPT;
_LIBCPP_END_UNVERSIONED_NAMESPACE_STD
#endif // _LIBCPP_ABI_VCRUNTIME

#endif // _LIBCPP___NEW_NEW_HANDLER_H
4 changes: 1 addition & 3 deletions libcxx/src/new_handler.cpp
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Expand Up @@ -11,9 +11,7 @@
#include "include/atomic_support.h"

#if defined(_LIBCPP_ABI_MICROSOFT)
# if !defined(_LIBCPP_ABI_VCRUNTIME)
# define _LIBPCPP_DEFINE_NEW_HANDLER
# endif
# define _LIBPCPP_DEFINE_NEW_HANDLER
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This doesn't seem right. The definitions provided __new_handler are dummy and non-conformant. Perhaps we should rely on VCRuntime's functionalities.

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@frederick-vs-ja frederick-vs-ja Jul 24, 2025 •
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I wonder whether we should include <vcruntime_new.h> instead of <new.h> (in other headers).

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I wonder whether we should include <vcruntime_new.h> instead of <new.h> (in other headers).

Unfortunately that would increase the scope of this PR, which is why it exists in standalone form rather than with #14899

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This doesn't seem right. The definitions provided __new_handler are dummy and non-conformant. Perhaps we should rely on VCRuntime's functionalities.

Care to elaborate? from what I've seen in MS-STL they both have similar implementations.

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I wonder whether we should include <vcruntime_new.h> instead of <new.h> (in other headers).

Unfortunately that would increase the scope of this PR, which is why it exists in standalone form rather than with #14899

I currently think that this is a simpler way to resolving declaration mismatch. If we don't do so, perhaps we need to define _CRTIMP2 properly in some configuration header.

This doesn't seem right. The definitions provided __new_handler are dummy and non-conformant. Perhaps we should rely on VCRuntime's functionalities.

Care to elaborate? from what I've seen in MS-STL they both have similar implementations.

The definitions provided in libcxx/src/new_handler.cpp don't interact with operator new/operator new[] (and thus non-conforming), and merely let the library compile under some conditions.

The proper implementations are expected to be provided by the underlying library (libsupc++, libc++abi, or VCRuntime, possibly along with some parts of MSVC STL).

#elif defined(LIBCXX_BUILDING_LIBCXXABI)
// nothing to do, we use the one from libc++abi
#elif defined(LIBCXXRT)
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7 changes: 0 additions & 7 deletions ...td/language.support/support.dynamic/alloc.errors/set.new.handler/get_new_handler.pass.cpp
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Expand Up @@ -8,13 +8,6 @@

// test get_new_handler

// FIXME: When libc++ is linked against vcruntime (i.e. the default config in
// MSVC mode), the declarations of std::set_new_handler and std::get_new_handler
// are provided by vcruntime/UCRT's new.h. However, that header actually only
// declares set_new_handler - it's missing a declaration of get_new_handler.

// XFAIL: msvc && stdlib=libc++

#include <new>
#include <cassert>

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