ipc: add windows support #32387

3577d23f616 ci: Enable -Wundef in default and llvm jobs
debd42955ea proxy-types: Avoid -Wundef error when KJ_NO_EXCEPTIONS is not defined
a8c64c7faa5 ci: Enable -Wunused-const-variable in GCC jobs
701449c1657 util: Make SocketError inline constexpr
6fd2a9c90e1 Merge bitcoin-core/libmultiprocess#367: mpgen: Change Cap'n Proto link order to fix undefined references in static builds
f1042b1a60e Merge bitcoin-core/libmultiprocess#366: ci: Compile with minimum supported g++-10 in olddeps
a6ecdc113ff Merge bitcoin-core/libmultiprocess#364: util: Error out at compile time if KJ_NO_EXCEPTIONS is set
56cfdaa884e Change CapnProto library linkage for mpgen
fa5633467af ci: Compile with minimum supported g++-10 in olddeps
4a1f400f8b7 util: Error out at compile time if KJ_NO_EXCEPTIONS is set
2dba130478a Merge bitcoin-core/libmultiprocess#363: ci: use LLVM 23 in Bitcoin Core CI
161197a5c7b Merge bitcoin-core/libmultiprocess#352: ci: add cmake debug output
fb4ac7eb8c8 ci: use LLVM 23 in Bitcoin Core CI
7bac69de1fc Merge bitcoin-core/libmultiprocess#360: pull latest .clang-tidy from downstream
79ddc44eb32 Merge bitcoin-core/libmultiprocess#359: ci: bump cmake version to 4.3.4 in newdeps job
bf229bf82ae Merge bitcoin-core/libmultiprocess#351: ci: do not ignore NIXPKGS_CHANNEL in local ci runs
073ac4f1972 Merge bitcoin-core/libmultiprocess#347: refactor: Replace EventLoop::post() with sync() taking kj::FunctionParam
fa1db7a9e3e pull latest .clang-tidy from downstream
5c49666a1d8 refactor: rename EventLoop::m_post_fn to m_sync_fn
2330fbe81e2 refactor: replace EventLoop::post() with sync() taking kj::FunctionParam
4d454a81da6 Merge bitcoin-core/libmultiprocess#358: refactor: Enable readability-container-contains
dba99582b32 Merge bitcoin-core/libmultiprocess#357: doc: Update Cap'n Proto version to match minimum
00923922ac3 Merge bitcoin-core/libmultiprocess#356: ci: Remove hard-coded -j4 from sanitize config
766867fb326 ci: clarify CAPNP_CHECKOUT=master is the v1.x release branch
cc3675280bf ci: bump cmake version to 4.3.4 in newdeps job
fa101113b50 refactor: Enable readability-container-contains
81f824b025f doc: Update Cap'n Proto version to match minimum
fa30e2093c7 ci: Remove hard-coded -j4 from sanitize config
a7ff9d5da22 ci: add cmake debug output
f2e8df82ede Merge bitcoin-core/libmultiprocess#350: cmake: add type-unordered-set.h and version.h to public headers
0e146c0468d Merge bitcoin-core/libmultiprocess#349: type-context: fix async disconnect race condition found by antithesis
49f95e26326 Merge bitcoin-core/libmultiprocess#212: ci: add newdeps job testing newer versions of cmake and capnproto
7c73cceda9b ci: rename CI-internal variables to use CI_ prefix
fe1b8339f00 ci: do not ignore NIXPKGS_CHANNEL in local ci runs
914dc839f27 proxy: fix data race between server request threads and disconnect handling
275c8eefdfb Merge bitcoin-core/libmultiprocess#345: Remove trailing whitespace and Add -Wtrailing-whitespace to default ci config
cd7162fb832 Merge bitcoin-core/libmultiprocess#304: proxy: fix BuildList to use non-const iteration for interface types
9b136782af1 ci: Add -Wtrailing-whitespace to default config
2f4be9ec6ea refactor: Remove trailing whitespace
2448d282ccd cmake: add type-unordered-set.h and version.h to public headers
b3fc922ee4a ci: add newdeps job testing newest versions of cmake and capnproto
390b5f901f1 Merge bitcoin-core/libmultiprocess#344: test: listen_tests and connect_tests follow-ups
d6f8588d1ab proxy: fix BuildList to use non-const iteration for interface types
e18ca520f45 Merge bitcoin-core/libmultiprocess#343: test: fix race in connect_tests disconnect-deferred-failure test
c39c7850c66 doc: note construct() call in valid init interface test
b9c36c61751 test: close sockets unconditionally and check errors with KJ_SYSCALL
7eb741e6359 test: drop unnecessary KJ_EXPECT(true)
113f1d4d287 test: join server thread unconditionally in connect tests
44bc4630bc1 test: drop mp:: prefixes in connect tests
038d33eb31e test: share DefaultLogHandler between test files
b54a1633085 test: drop TestSetup socket members in connect tests
70467c5a727 test: add m_ prefix to TestSetup members in connect tests
cc260f2526f test: replace capnp fix link with upstream PR
137a6e4e039 test: fix race in connect_tests disconnect-deferred-failure test
8dab0d4bdeb Merge bitcoin-core/libmultiprocess#341: ci: add -Wextra-semi to llvm config
b3b134eed8b ci: add -Wextra-semi to llvm config
bdd0cd69418 Merge bitcoin-core/libmultiprocess#339: refactor: add `[[noreturn]]` attributes
a779a09764c ci: add -Wmissing-noreturn
636aaff576b refactor: add missing [[noreturn]] attributes
cc11c2b1b41 Merge bitcoin-core/libmultiprocess#338: test: check ReadList return value
2d6e863c77a Merge bitcoin-core/libmultiprocess#334: ci: Set CMAKE_BUILD_PARALLEL_LEVEL to enable parallelism by default
d4d10ff98ab Merge bitcoin-core/libmultiprocess#332: ci: add -Wextra-semi to default config
b540e70f25f Merge bitcoin-core/libmultiprocess#324: proxy: Name threads spawned by the event loop
e5e367e785c Merge bitcoin-core/libmultiprocess#312: util: report back child errors to parent and throw
2220df68c91 Merge bitcoin-core/libmultiprocess#298: Fix error handling when creating clients (`mp::ConnectStream`)
51defb79ef7 Merge bitcoin-core/libmultiprocess#340: ci: Update `capnproto` prerequisites on NetBSD
7e94790b08a ci: Update `capnproto` prerequisites on NetBSD
9f25ffca5b0 test: Cover OS thread names for worker, pool, and async threads
648a18589c4 proxy: Name threads spawned by the event loop
49834b2609e ci: add -Wextra-semi to default config
fae9a637e35 example: Remove unused kj/async.h include
bb473690c97 Fix error handling when creating clients
44d191420c6 Add test coverage for ConnectStream
231361ae5af Correct stale UnixListener doc comment
060c1a50d03 Extract `UnixListener` class to a dedicated file
62f25af06c3 test: check ReadList return value
ce51d737255 ci: Set CMAKE_BUILD_PARALLEL_LEVEL to enable parallism in build jobs by default
67302cd132a Merge bitcoin-core/libmultiprocess#331: Remove code for Cap'n Proto versions before 0.9
f13c64ab54e Merge bitcoin-core/libmultiprocess#330: ci: Compile with minimum supported g++ in olddeps
8e026f66252 Merge bitcoin-core/libmultiprocess#327: build: avoid unnecessary capnp-rpc dependency for mpgen
e5206e9eb5b Merge bitcoin-core/libmultiprocess#325: cmake: Remove `QUIET` option from `find_package(CapnProto ...)`
879efea2bc7 Merge bitcoin-core/libmultiprocess#321: ci: Roll NetBSD releases to 11.0, drop 9.4
abf127a3141 Merge bitcoin-core/libmultiprocess#317: ipc: Fix mpgen capnp tool path for vcpkg/Windows builds
c437d7f107e Merge bitcoin-core/libmultiprocess#310: test: cover immediate client disconnects for `ListenConnections`
31bff8a673f Merge bitcoin-core/libmultiprocess#307: refactor: memcpy -> std::ranges::copy
f355108b0a0 Merge bitcoin-core/libmultiprocess#303: type-chrono: Add CustomBuildField/CustomReadField overloads for std::chrono::time_point
2d678177c14 Merge bitcoin-core/libmultiprocess#296: ci: Bump channel to nixos-26.05
3f05b11624c util: kill and reap child on SpawnProcess error
4a56c1837a7 util: report back child error to parent and throw
a9e70dbe775 ci: Add NetBSD release 11.0
2d33b14fb0e ci: Switch to default compiler on NetBSD 9.4
36f74002775 ci: Drop NetBSD release 9.4
bd508311b56 refactor: Drop stray semicolons after function definitions
788f17a8509 Remove code for Cap'n Proto versions before 0.9
7402affd0ce ci: Pin oldeps config to older nixpkgs channel to compile older cmake with older gcc
edf63435624 ci: Compile with minimum supported g++-11 in olddeps
fa47449afe1 cmake: avoid unnecessary capnp-rpc dependency for mpgen
a494b764de5 cmake: Remove `QUIET` option from `find_package(CapnProto ...)`
26452e02d75 refactor: memcpy -> std::ranges::copy
e1dcc6eb182 Merge bitcoin-core/libmultiprocess#316: cmake: Fix stale codegen when mpgen binary changes
7a72df02e2d type-chrono: Add CustomBuildField/CustomReadField overloads for std::chrono::time_point
45b685c3f58 type-number, type-chrono: Fix static assert signed/unsigned comparisons
45f6255975d type-number: exclude bool from the integral overload
8d6d4649482 Merge bitcoin-core/libmultiprocess#315: Fix startup race in example
a6fc80d2547 Merge bitcoin-core/libmultiprocess#311: bugfix: clear FD_CLOEXEC in child instead of parent before fork
496fb84e69f test: cover immediate client disconnects for `ListenConnections`
36c6c63520e doc: Document reference-counted EventLoop lifetime
3a997e113cf Fix startup race in mpexample
f5c15ce33ff Merge bitcoin-core/libmultiprocess#323: refactor: access ThreadContext through CurrentThread(), ci: switch Bitcoin Core to master
66298c737f4 ci: Switch back to Bitcoin Core's master branch
86b48105018 refactor: access ThreadContext through CurrentThread()
eea9c64f6e1 cmake: Fix stale codegen when mpgen binary changes
a26a08496b8 cmake: Fix mpgen capnp tool path for vcpkg/Windows builds
140d9ba6ff7 test: allow custom log handler in `ListenSetup`
1e0c7ff9a51 util: Clear FD_CLOEXEC in child instead of parent before fork
8550ee6a317 util, refactor: Add ChildFail helper for post-fork child errors
17eab90b526 test: Fix typo in listen_tests.cpp
ce865a9ba86 refactor: Directly use value in CustomBuildField
3f221b5bfd7 Merge bitcoin-core/libmultiprocess#274: Add nonunix platform support
1b0f6056062 doc: Remove trailing whitespace
d8f8ca3119f ipc: Wrap mpgen main() in try-catch to print errors
fbe5a14ad46 ci: Check out bitcoin/bitcoin PR #35084 instead of master
39d3690d83d types: Replace SFINAE with requires clauses to avoid MSVC C2039 error
ba68520203c proxy, refactor: Fix C4305 truncation warning in Accessor on MSVC
1d81d47811e util, refactor: Fix PtrOrValue constructor for move-only types on MSVC
b883fe1e527 proxy: Fix shutdownWrite() exception handling on macOS with dynamic libraries
0012411ccc6 proxy: Call shutdownWrite() in Connection destructor
38312ad1912 proxy, refactor: Change ConnectStream and ServeStream to accept stream objects
e96d5d742ab proxy, refactor: Replace EventLoop wakeup fd integers with KJ stream objects
db4f9a3d739 cmake: Bump minimum required Cap'n Proto version to 0.9
652934fb793 util, refactor: Add SocketPair() and use it in SpawnProcess
1c6ef7a26c0 util, refactor: Do not fork() and exec() separately
1389cf3132f util, refactor: Add SpawnConnectInfo type alias and use it
c7ca1f00b62 util, refactor: Add SocketId type alias and use it
be46a35203c util, refactor: Add ProcessId type alias and use it
91a78db7808 doc: Bump version 13 > 14
fa2c56ec27f ci: Bump channel to nixos-26.05

git-subtree-dir: src/ipc/libmultiprocess
git-subtree-split: 3577d23f616ec6e8d601d14452a5793f9d386708

Lambda [[noreturn]] attributes before the parameter list are a C++23
extension intentionally used in C++20 builds (needed for compatibility
with -Wmissing-noreturn). Suppress the extension warning rather than
removing the attributes or working around them.

Uses the existing IF_CHECK_PASSED idiom so GCC, which silently ignores
unknown -Wno-* flags, is unaffected.

This change was written with Claude Sonnet 4.6.

Switch from _execvp to _spawnvp(_P_NOWAIT) + _cwait so bitcoin.exe
waits for the child process to finish and forwards its exit code.
Previously _execvp would exit the parent as soon as the child started,
making it impossible for anything waiting on bitcoin.exe (such as a test
framework) to track whether the child succeeded or failed. _P_NOWAIT is
used instead of _P_WAIT so that a child exit code of -1 (0xffffffff) is
not confused with a spawn failure: _spawnvp(_P_WAIT) returns -1 for both,
but _spawnvp(_P_NOWAIT) returns the child handle on success, and _cwait
fills a separate status that is forwarded via _exit.

Co-Authored-By: Bortlesboat <169967362+Bortlesboat@users.noreply.github.com>
This change was written with Claude Sonnet 4.6.

Now that util::ExecVp on Windows uses _spawnvp(_P_NOWAIT) + _cwait
instead of _execvp, the bitcoin wrapper process blocks until the child
exits and Python can capture its stdout/stderr and exit code normally.
Remove the Windows skips added in #33229 and #35551.

The interface_gui.py test is still skipped in vcpkg Qt builds. vcpkg builds Qt
with -opengl dynamic, making the minimal platform plugin unusable due to
internal Qt bugs. This matches existing logic in src/qt/test/CMakeLists.txt
avoiding the minimal platform plugin with test_bitcoin-qt. A comment
there is also updated for clarity.

Co-Authored-By: Hodlinator <172445034+hodlinator@users.noreply.github.com>

Switch from system_category to generic_category when throwing from
ExecVp failure, so errno is read as a POSIX value. On Windows,
system_category interprets codes as Win32 errors, so EINVAL=22 would
produce "The device does not recognize the command" instead of
"Invalid argument".

This change was written with Claude Sonnet 4.6.

WARNING: DO NOT MERGE — this draft PR modifies the libmultiprocess
subtree directly (intentionally, for testing purposes) which causes
the subtree link check to fail. Disabling the check here to avoid
masking unrelated lint failures while the PR is open for testing.

Restore the omitted entry before any merge attempt.

Note: removing src/ipc/libmultiprocess from get_subtrees() also removes
it from get_pathspecs_default_excludes(), so all other lint checks
(trailing newline, whitespace, etc.) now run on files in that directory
as well. This is why src/ipc/libmultiprocess/include/mp/type-unordered-set.h
needs a trailing newline added here even though it is not otherwise
modified by this PR: it has always been missing the newline, but was
previously hidden from the lint check by the subtree exclusion.

This change was written with Claude Sonnet 4.6.

Remove recently introduced SpawnConnectInfo and SpawnConnectInfoToArgsFn type
aliases since they are the same on all platforms and might obscure the fact
that connect info should be treated as an opaque string.

Co-authored-by: Sjors Provoost <sjors@sprovoost.nl>

This change was written with Claude Sonnet 4.6.

Replace the Unix-only UnixListener test helper with a cross-platform
SocketListener backed by a std::variant<sockaddr_un> (TCP arm will be
added later for Wine compatibility).

- test/socketlistener.h: New header with SocketListener class extracted from
  the pattern of UnixListener but using SocketId/SocketError types,
  std::filesystem for temp dir cleanup, and mp::CloseSocket for teardown.
  Uses std::variant<sockaddr_un> so the TCP arm can be appended later without
  restructuring the class.
- test/unixlistener.h: Deleted.
- test/listen_tests.cpp: Switch to socketlistener.h and socketlistener.
- test/connect_tests.cpp: Switch to socketlistener.h and socketlistener.

This change was written with Claude Sonnet 4.6.

Move POSIX-only headers in util.cpp into a #ifndef WIN32 block so the file
compiles on Windows without modification. Guard the Unix-only helpers (MakeArgv,
MaxFd, ChildFail, SpawnError*, ReadSpawnResult, WriteSpawnError, KillAndReapChild)
with a single #ifndef WIN32 block. Guard the extern "C" environ declaration
likewise. Guard Unix-only includes in spawn_tests.cpp and connect_tests.cpp and
wrap the Unix-only spawn tests with #ifndef WIN32.

No Windows implementations are added here; those come in a later commit.

This change was written with Claude Sonnet 4.6.

Co-authored-by: Sjors Provoost <sjors@sprovoost.nl>

Add Windows-specific code to support building and running on Windows:

- util.h: Guard ProcessId/SocketId/SocketError type aliases with WIN32
  ifdefs so they use SOCKET/uintptr_t on Windows and int on Unix.
  Add winsock2.h include on Windows.
- util.cpp: Guard Unix-specific system headers with WIN32 ifdefs. Add
  Windows-specific includes (windows.h, winsock2.h). Guard MaxFd() with
  #ifndef WIN32. Add GetCurrentThreadId() branch in ThreadName(). Add
  win32Socketpair() forward-declare. Add Windows branch in SocketPair()
  using win32Socketpair(). Add CommandLineFromArgv() helper needed to
  construct CreateProcess command lines. Add Windows branch in
  SpawnProcess() using named pipes and WSADuplicateSocket to pass socket
  to child. Add Windows branch in StartSpawned() reading socket from
  named pipe. Add Windows branch in WaitProcess() using
  WaitForSingleObject/GetExitCodeProcess.
- proxy.cpp: Add SocketOutputStream class on Windows (analogous to
  FdOutputStream but using SOCKET/send()). Add Windows branch in
  EventLoop constructor to create m_post_writer using SocketOutputStream.

Co-Authored-By: ViniciusCestarii <viniciuscestari01@gmail.com>

SpawnProcess on Windows creates a named pipe with PIPE_WAIT and then calls
ConnectNamedPipe synchronously. If the child exits or crashes before
connecting, ConnectNamedPipe blocks forever with no recovery path.

Fix by opening the pipe with FILE_FLAG_OVERLAPPED and using
WaitForMultipleObjects on both the connect event and the child process
handle. If the process handle signals first, the child died without
connecting and SpawnProcess throws instead of hanging. Since the pipe is
now in overlapped mode, WriteFile also requires an OVERLAPPED structure;
use GetOverlappedResult with bWait=TRUE to handle both synchronous and
asynchronous completion.

Add a Windows-only test that spawns a child which exits immediately
without opening the named pipe and asserts SpawnProcess does not block.

(https://github.com/bitcoin-core/libmultiprocess/pull/231#discussion_r3706021950)

Co-Authored-By: ViniciusCestarii <viniciuscestari01@gmail.com>
This change was written with Claude Sonnet 4.6.

Allow code to compile without pthreads available, as required for MSVC
compatibility. Avoid unconditional POSIX calls (fork, posix_spawn,
pthread_getname_np) by moving them into #ifndef WIN32 or HAVE_PTHREAD_*
guards. When pthreads is available on Windows (detected via cmake
HAVE_PTHREAD_* checks), still use it for thread name reporting since it
provides useful information at low cost.

Also add Threads::Threads as an explicit dependency of the multiprocess
library. proxy.cpp directly uses thread_local, std::this_thread, and
std::thread, and the dependency was previously satisfied only through
transitive linkage from CapnProto::kj-async.

This change was written with Claude Sonnet 4.6.

Add TCP (sockaddr_in) support to SocketListener and platform-conditional
header guards so the class compiles and works on Windows:

- Wrap POSIX headers (arpa/inet.h, netinet/in.h, sys/socket.h, sys/un.h)
  in #else of #ifdef WIN32, with Windows equivalents (afunix.h,
  ws2tcpip.h) in the #ifdef WIN32 branch.
- Add a WsaInit static initializer on Windows that calls WSAStartup
  before any socket operations. Tests create sockets directly (not via
  StartSpawned), so Winsock must be initialized here.
- Add Init(sockaddr_in&) and Connect(const sockaddr_in&) overloads for
  TCP loopback connections.
- Use TCP on Windows to work around Wine's lack of the AcceptEx extension
  required by KJ's AF_UNIX listener; Unix platforms continue using
  AF_UNIX.
- Expand std::variant<sockaddr_un> to std::variant<sockaddr_in, sockaddr_un>.

This change was written with Claude Sonnet 4.6.

- shell.nix: add `windows` parameter that selects pkgs.pkgsCross.mingwW64
  as the cross target; also change crossPkgs default from import<nixpkgs>{}
  to null (cleaner API). When windows=true, add native pkgs.capnproto to
  nativeBuildInputs so capnp/capnpc-c++ are in PATH for cmake code generation,
  and add wine64Packages.staging so ctest can run mptest.exe via wine.
  Change llvmBase to always use pkgs (native) instead of crossPkgs.

- ci/configs/windows.bash: new config that cross-compiles with mingw,
  sets CMAKE_SYSTEM_NAME=Windows, CMAKE_FIND_ROOT_PATH_MODE_PROGRAM=NEVER
  (so cmake finds native capnp from PATH), CMAKE_CROSSCOMPILING_EMULATOR=wine
  (so ctest runs mptest.exe via wine), and sets MPGEN_PRE_BUILD=1.

- ci/scripts/ci.sh: add MPGEN_PRE_BUILD support: when set, build native mpgen
  in $CI_DIR-native before the main cross build, then inject
  -DMPGEN_EXECUTABLE into CMAKE_ARGS. This is needed because cmake's
  add_custom_command does not use CMAKE_CROSSCOMPILING_EMULATOR, so the
  cross-compiled mpgen.exe cannot be used as a code generator directly.

This change was written with Claude Sonnet 4.6.

MinGW has a bug where thread_local destructors can run on already-freed memory
at thread exit, causing heap corruption. MSVC builds and non-Windows platforms
are unaffected.

This caused intermittent STATUS_HEAP_CORRUPTION in MinGW CI builds when
~ThreadContext walked freed memory at thread exit. See CurrentThread() in
proxy-io.h for the full explanation and upstream bug references.

Workaround: change CurrentThread() accessor in MinGW builds to return a
heap-allocated object held by a trivially-destructible pointer, skipping
destructor registration at thread exit. The object is deliberately
leaked.

This change was written with Claude Fable 5.

Various small fixes for making ENABLE_IPC build work on windows.

MSVC does not provide mkstemp (a POSIX function available in MinGW but
not the MSVC runtime), causing:

  error C3861: 'mkstemp': identifier not found
  error C4996: 'close': The POSIX name for this item is deprecated

Fix by using _mktemp_s on WIN32, which fills in the XXXXXX suffix
in-place without creating a file (so no fd to close or file to remove).

This change was written with Claude Sonnet 4.6.

On Windows, connect() to a Unix domain socket path that doesn't exist
may return a WSA error code (e.g. WSAECONNREFUSED) that doesn't map to
std::errc::no_such_file_or_directory via std::system_category(), unlike
POSIX where ENOENT is returned. After a failed connect, explicitly check
if the socket path exists and throw the expected error if not.

Also add an fs::exists(path, ec) overload to fs.h: the file's existing
exists() wrappers shadow std::filesystem::exists(path, error_code&),
causing the new call in process.cpp to fail to compile under MinGW.

This change was written with Claude Sonnet 4.6.

When the IPC socket file exists but no node is listening, ProcessImpl::connect
throws std::system_error(WSAECONNREFUSED, std::system_category()). MinGW
libstdc++'s system_category() does not map Winsock error values to std::errc
conditions, so the std::errc::connection_refused check in connectAddress fails
to catch it, and bitcoin-cli -ipcconnect=auto throws CConnectionFailed instead
of falling back to HTTP.

This is a workaround: the proper fix is for ProcessImpl::connect to throw
std::errc::connection_refused (using generic_category) rather than relying on
system_category() to map Winsock codes. As a workaround, check for
WSAECONNREFUSED explicitly in system_category on WIN32.

MSVC's STL does map WSAECONNREFUSED to errc::connection_refused, so this
check is redundant but harmless there.

This change was written with Claude Fable 5.

Bug: MSVC C2131 "expression did not evaluate to a constant" on line:
  static_assert(ipc::capnp::messages::MAX_DOUBLE == std::numeric_limits<double>::max())

Root cause: Capnp floating-point constants can't be constexpr on MSVC.
In capnp's generated-header-support.h, CAPNP_NON_INT_CONSTEXPR_DECL_INIT
is defined as empty on MSVC (with the comment "MSVC doesn't understand
floating-point constexpr yet"), so MAX_DOUBLE is declared as
`static const double MAX_DOUBLE;` without an initializer in the header.
A `const double` (unlike `const int`) is not a constant expression in C++,
so it can't be used in static_assert on MSVC.

Fix: Guard with `#if !defined(_MSC_VER) || defined(__clang__)` to match
the exact condition capnp itself uses for the same limitation. The other
three static_asserts in the same block use integer constants (MAX_MONEY,
DEFAULT_BLOCK_RESERVED_WEIGHT, DEFAULT_COINBASE_OUTPUT_MAX_ADDITIONAL_SIGOPS)
which don't have this MSVC limitation and continue to run.

Alternatives considered:
- Convert to a runtime BOOST_CHECK: would require moving into a test
  function, more invasive change.
- Use std::numeric_limits<double>::max() literal: wouldn't help since
  MAX_DOUBLE is the non-constexpr side.

This change was written with Claude Sonnet 4.6.

Python's asyncio doesn't support create_unix_connection() on Windows. Implement
it by patching asyncio.ProactorEventLoop, using ctypes ws2_32.connect() and
a non-blocking select() loop. See ipc_util.py for details on why each of those
choices was necessary.

Also: run blocking do_fn() callables in run_in_executor() in wait_and_do();
unlink stale AF_UNIX socket files before node restart on Windows (test_node.py);
set UNIX_PATH_MAX = 108 for Windows (test_node.py); catch OSError in the
connection retry loop in interface_ipc_mining.py.

This change was written with Claude Sonnet 4.6.

On POSIX, connect() to a stopped node returns ECONNREFUSED and bitcoin-cli
prints "error: Connection refused" followed by help text. On Windows the
equivalent WSAECONNREFUSED produces a different OS error string without help
text. Fix the expected string and switch to a prefix match since the Windows
message has no appended help text.

Also, on Windows, bitcoind removes the IPC socket file on clean shutdown
(unlike Linux where the file persists and connect() returns ECONNREFUSED).
A subsequent connect attempt sees ENOENT ("No such file or directory").
Update test_cli() to accept a tuple of alternative prefixes and use a
two-entry tuple for the Windows case covering both error strings.

Also add diagnostic logging retained for future debugging: ipc_socket_path
in both backslash and forward-slash forms with encoded byte length (to
diagnose MinGW path format issues), socket file existence before each
explicit-path test, and per-call debug logging of returncode and stdout.

This change was written with Claude Sonnet 4.6.

Add a helper function that generates a target-specific resource file from a
template and links it along with an application manifest, replacing the static
per-binary *-res.rc files previously used by non-GUI executables and the
bitcoin-qt-res.rc previously used by GUI executables.

The new add_windows_exe_resources(target description [ICON_DIR dir]) function
in AddWindowsResources.cmake handles both GUI and non-GUI executables through a
single cmake/windows-res.rc.in template. When ICON_DIR is provided, the
function prepends icon declarations to the generated RC file and sets
ProductName to the project name, matching the previous GUI-specific behavior.

Also adds the missing add_windows_exe_resources() call for bitcoin-node, which
previously had no resource section and caused the Windows CI manifest
validation check (mt.exe -validate_manifest) to fail.

This change was written with Claude Sonnet 4.6.

Remove -DENABLE_IPC=OFF from the win64 cross-build environment file
and install pycapnp in the Windows cross-build test runner. The
depends/ system already builds capnp for the MinGW target (NO_IPC is
not set), so cmake will find it via the toolchain file. This lets
interface_ipc.py and related tests run in the "Windows, test
cross-built" CI jobs.

This change was written with Claude Sonnet 4.6.

Add an "ipc" feature to vcpkg.json with capnproto as a dependency and
include it in default-features, so the Windows native VS CI job installs
capnproto when ENABLE_IPC is ON (the default). The fuzz build already
uses VCPKG_MANIFEST_NO_DEFAULT_FEATURES=ON, so it is unaffected.

Also install pycapnp in ci-windows.py alongside pyzmq so the IPC
functional tests (interface_ipc.py) have their required Python library,
matching what every other CI platform already does.

This change was written with Claude Sonnet 4.6.

The fuzz build in ci-windows.py set -DVCPKG_MANIFEST_FEATURES=wallet but
omitted ipc and tests, so vcpkg installed wallet dependencies but not
capnproto. The build then failed with:
  "Cap'n Proto is required but was not found"

Fix: extend VCPKG_MANIFEST_FEATURES to ipc;tests;wallet.

This change was written with Claude Sonnet 4.6.

The proxy-server code generated for test/mp/test/foo.capnp now has more
sections than MSVC's default object file format allows, failing the
Windows native VS CI job with "error C1128: number of sections exceeded
object file format limit: compile with /bigobj"
(https://github.com/bitcoin/bitcoin/actions/runs/36945085020/job/110645241551).
Bitcoin Core already passes /bigobj for its own debug builds.

Not reproduced locally; based on the error message.

This change was written with Claude Opus 5.5 (1M context).