Define guard macros to prevent windows.h from conflicting with winsoc…

…k2.h

CMakeLists.txt

@@ -221,7 +221,9 @@ if(USE_CUDA)
 
   find_package(CUDAToolkit REQUIRED)
   find_package(CCCL CONFIG)
-  if(NOT CCCL_FOUND)
+  if(CCCL_FOUND)
+    message(STATUS "Standalone CCCL found.")
+  else()
     message(STATUS "Standalone CCCL not found. Attempting to use CCCL from CUDA Toolkit...")
     find_package(CCCL CONFIG
       HINTS ${CUDAToolkit_LIBRARY_DIR}/cmake)
@@ -238,6 +240,10 @@ if(USE_CUDA)
       target_link_libraries(CCCL::CCCL INTERFACE libcudacxx::libcudacxx CUB::CUB Thrust)
     endif()
   endif()
+  # Define guard macros to prevent windows.h from conflicting with winsock2.h
+  if(WIN32)
+    target_compile_definitions(CCCL::CCCL INTERFACE NOMINMAX WIN32_LEAN_AND_MEAN _WINSOCKAPI_)
+  endif()
 endif()
 
 if(FORCE_COLORED_OUTPUT AND (CMAKE_GENERATOR STREQUAL "Ninja") AND

include/xgboost/collective/socket.h

@@ -99,6 +99,7 @@ inline auto ThrowAtError(StringView fn_name, std::int32_t errsv = LastError()) {
 using SocketT = SOCKET;
 #else
 using SocketT = int;
+#define INVALID_SOCKET -1
 #endif  // defined(_WIN32)
 
 #if !defined(xgboost_CHECK_SYS_CALL)
@@ -276,7 +277,7 @@ class TCPSocket {
   SockDomain domain_{SockDomain::kV4};
 #endif
 
-  constexpr static HandleT InvalidSocket() { return -1; }
+  constexpr static HandleT InvalidSocket() { return INVALID_SOCKET; }
 
   explicit TCPSocket(HandleT newfd) : handle_{newfd} {}
 

include/xgboost/windefs.h

@@ -20,7 +20,13 @@
 #endif  // !defined(NOMINMAX)
 
 // A macro used inside `windows.h` to avoid conflicts with `winsock2.h`
+#if !defined(WIN32_LEAN_AND_MEAN)
 #define WIN32_LEAN_AND_MEAN
+#endif  // !defined(WIN32_LEAN_AND_MEAN)
+// Stop windows.h from including winsock.h
+#if !defined(_WINSOCKAPI_)
+#define _WINSOCKAPI_
+#endif  // !defined(_WINSOCKAPI_)
 
 #if !defined(xgboost_IS_MINGW)