Hello. As Windows Arm64 platform does not carry historical compatibility layers, the structure of Windows API DLLs is cleaner on Arm64 than on x64. For this reason, the x64 linking against `kernel32.dll` is not sufficient leading to undefined references to many Windows API symbols that are in different DLLs that would have to be added to the linking command explicitly.
To address that, there is a concept of umbrella DLLs (https://learn.microsoft.com/en-us/windows/win32/apiindex/windows-umbrella-libraries), that can be added instead. The recommended replacement for `kernel32.dll` is `onecore.dll` (https://learn.microsoft.com/en-us/windows-hardware/drivers/develop/building-for-onecore#building-for-onecore) that should be available since Windows 7. In case of Cygwin linking, there is one exception, `pdh.dll` (Performance Data Helper, https://learn.microsoft.com/en-us/windows/win32/perfctrs/performance-counters-functions), that is not included in the `onecore.dll`. Radek --- >From 5a34927952b62bd273610ab85974922a7411375b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Radek=20Barto=C5=88?= <radek.bar...@microsoft.com> Date: Mon, 9 Jun 2025 13:08:09 +0200 Subject: [PATCH] Cygwin: resolve AArch64 linking by linking to onecore instead of kernel32 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit As Windows Arm64 platform does not carry historical compatibility layers, he structure of Windows API DLLs is cleaner on Arm64 than on x64. For this reason, the x64 linking against kernel32.dll is not sufficient leading to undefined references to many Windows API symbols that are in different DLLs that would have to be added to the linking command explicitly. To address that, there is a concept of umbrella DLLs (https://learn.microsoft.com/en-us/windows/win32/apiindex/windows-umbrella-libraries), that can be added instead. The recommended replacement for kernel32.dll is onecore.dll (https://learn.microsoft.com/en-us/windows-hardware/drivers/develop/building-for-onecore#building-for-onecore) that should be available since Windows 7. In case of Cygwin linking, there is one exception, pdh.dll (Performance Data Helper, https://learn.microsoft.com/en-us/windows/win32/perfctrs/performance-counters-functions), that is not included in the onecore.dll. Signed-off-by: Radek BartoĊ <radek.bar...@microsoft.com> --- winsup/cygwin/Makefile.am | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/winsup/cygwin/Makefile.am b/winsup/cygwin/Makefile.am index 90a7332a8..96d1ab2f5 100644 --- a/winsup/cygwin/Makefile.am +++ b/winsup/cygwin/Makefile.am @@ -629,7 +629,7 @@ $(NEW_DLL_NAME): $(LDSCRIPT) libdll.a $(VERSION_OFILES) $(LIBSERVER)\ $(LIBSERVER) \ $(newlib_build)/libm.a \ $(newlib_build)/libc.a \ - -lgcc -lkernel32 -lntdll -Wl,-Map,cygwin.map + -lgcc -lpdh -lntdll -lonecore -Wl,-Map,cygwin.map @$(MKDIR_P) ${target_builddir}/winsup/testsuite/testinst/bin/ $(AM_V_at)$(INSTALL_PROGRAM) $(NEW_DLL_NAME) ${target_builddir}/winsup/testsuite/testinst/bin/$(DLL_NAME) -- 2.50.1.vfs.0.0
0001-Cygwin-resolve-AArch64-linking-by-linking-to-onecore-instead-of-kernel32.patch
Description: 0001-Cygwin-resolve-AArch64-linking-by-linking-to-onecore-instead-of-kernel32.patch
