diff --git a/zookeeper-client/zookeeper-client-c/CMakeLists.txt b/zookeeper-client/zookeeper-client-c/CMakeLists.txt
index da1351e20f5..c506d114369 100644
--- a/zookeeper-client/zookeeper-client-c/CMakeLists.txt
+++ b/zookeeper-client/zookeeper-client-c/CMakeLists.txt
@@ -23,24 +23,24 @@ set(description "zookeeper C client")
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/../../tools/cmake/Modules")
 
 # general options
-if(UNIX)
-  add_compile_options(-Wall -fPIC)
-elseif(WIN32)
+if(MSVC)
   add_compile_options(/W3)
+elseif(MINGW)
+  add_compile_options(-Wall)
+else()
+  add_compile_options(-Wall -fPIC)
 endif()
-add_definitions(-DUSE_STATIC_LIB)
+
+option(BUILD_SHARED_LIBS "Build ZooKeeper client shared libraries" OFF)
+option(BUILD_STATIC_LIBS "Also build ZooKeeper client static libraries" OFF)
 
 # TODO: Enable /WX and /W4 on Windows. Currently there are ~1000 warnings.
 # TODO: Add Solaris support.
-# TODO: Add a shared library option.
 # TODO: Specify symbols to export.
 # TODO: Generate doxygen documentation.
 
 # Sync API option
 option(WANT_SYNCAPI "Enables Sync API support" ON)
-if(WANT_SYNCAPI)
-  add_definitions(-DTHREADED)
-endif()
 
 # CppUnit option
 if(WIN32 OR APPLE)
@@ -130,6 +130,11 @@ endforeach()
 
 # function checks
 include(CheckFunctionExists)
+set(ZOOKEEPER_SAVED_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
+if(WIN32)
+  # Winsock functions cannot be detected unless the probe links ws2_32.
+  list(APPEND CMAKE_REQUIRED_LIBRARIES ws2_32)
+endif()
 set(check_functions
   getcwd
   gethostbyname
@@ -147,10 +152,20 @@ set(check_functions
   strerror
   strtol)
 
+# CheckFunctionExists cannot detect 32-bit stdcall Winsock symbols because it
+# does not include their declarations, so record the known Windows APIs.
+if(WIN32)
+  set(HAVE_GETHOSTBYNAME 1)
+  set(HAVE_GETHOSTNAME 1)
+  set(HAVE_SOCKET 1)
+endif()
+
 foreach(fn ${check_functions})
   to_have(${fn} name)
   check_function_exists(${fn} ${name})
 endforeach()
+set(CMAKE_REQUIRED_LIBRARIES ${ZOOKEEPER_SAVED_REQUIRED_LIBRARIES})
+unset(ZOOKEEPER_SAVED_REQUIRED_LIBRARIES)
 
 # library checks
 set(check_libraries rt m pthread)
@@ -161,7 +176,13 @@ endforeach()
 
 # IPv6 check
 include(CheckStructHasMember)
-check_struct_has_member("struct sockaddr_in6" sin6_addr "netinet/in.h" ZOO_IPV6_ENABLED)
+if(WIN32)
+  check_struct_has_member("struct sockaddr_in6" sin6_addr
+    "winsock2.h;ws2tcpip.h" ZOO_IPV6_ENABLED)
+else()
+  check_struct_has_member("struct sockaddr_in6" sin6_addr
+    "netinet/in.h" ZOO_IPV6_ENABLED)
+endif()
 
 # configure
 configure_file(cmake_config.h.in ${CMAKE_CURRENT_BINARY_DIR}/include/config.h)
@@ -172,8 +193,8 @@ add_library(hashtable STATIC ${hashtable_sources})
 target_include_directories(hashtable PUBLIC include)
 target_link_libraries(hashtable PUBLIC $<$<OR:$<PLATFORM_ID:Linux>,$<PLATFORM_ID:FreeBSD>>:m>)
 
-# zookeeper library
-set(zookeeper_sources
+# ZooKeeper client libraries
+set(zookeeper_common_sources
   src/zookeeper.c
   src/recordio.c
   generated/zookeeper.jute.c
@@ -181,37 +202,72 @@ set(zookeeper_sources
   src/zk_hashtable.c
   src/addrvec.c)
 
-if(WANT_SYNCAPI)
-  list(APPEND zookeeper_sources src/mt_adaptor.c)
-else()
-  list(APPEND zookeeper_sources src/st_adaptor.c)
-endif()
-
 if(CYRUS_SASL_FOUND)
-  list(APPEND zookeeper_sources src/zk_sasl.c)
+  list(APPEND zookeeper_common_sources src/zk_sasl.c)
 endif()
 
 if(WIN32)
-  list(APPEND zookeeper_sources src/winport.c)
+  list(APPEND zookeeper_common_sources src/winport.c)
 endif()
 
-add_library(zookeeper STATIC ${zookeeper_sources})
-target_include_directories(zookeeper PUBLIC include ${CMAKE_CURRENT_BINARY_DIR}/include generated)
-target_link_libraries(zookeeper PUBLIC
-  hashtable
-  $<$<PLATFORM_ID:Linux>:rt> # clock_gettime
-  $<$<PLATFORM_ID:Windows>:ws2_32>) # Winsock 2.0
+function(add_zookeeper_library target variant library_type adaptor)
+  add_library(${target} ${library_type}
+    ${zookeeper_common_sources} ${adaptor})
+  target_include_directories(${target} PUBLIC
+    include ${CMAKE_CURRENT_BINARY_DIR}/include generated)
+  target_link_libraries(${target} PUBLIC
+    hashtable
+    $<$<PLATFORM_ID:Linux>:rt> # clock_gettime
+    $<$<PLATFORM_ID:Windows>:ws2_32>) # Winsock 2.0
+  set_target_properties(${target} PROPERTIES OUTPUT_NAME zookeeper_${variant})
+
+  if("${library_type}" STREQUAL "SHARED")
+    if(WIN32)
+      # ZOOAPI expands to dllexport while compiling the DLL and dllimport for
+      # consumers. Export the remaining public generated/Jute entry points too.
+      target_compile_definitions(${target} PRIVATE DLL_EXPORT)
+      set_target_properties(${target} PROPERTIES WINDOWS_EXPORT_ALL_SYMBOLS ON)
+    endif()
+  else()
+    target_compile_definitions(${target} PUBLIC USE_STATIC_LIB)
+  endif()
+
+  if("${variant}" STREQUAL "mt")
+    target_compile_definitions(${target} PUBLIC THREADED)
+  endif()
+
+  set(zookeeper_library_targets ${zookeeper_library_targets} ${target} PARENT_SCOPE)
+endfunction()
+
+# Keep the historical CMake default (static only).  Turning on both options
+# produces static and shared artifacts in one build tree.
+set(zookeeper_library_targets)
+if(BUILD_SHARED_LIBS)
+  add_zookeeper_library(zookeeper_st_shared st SHARED src/st_adaptor.c)
+  if(WANT_SYNCAPI)
+    add_zookeeper_library(zookeeper_mt_shared mt SHARED src/mt_adaptor.c)
+  endif()
+endif()
+
+if(NOT BUILD_SHARED_LIBS OR BUILD_STATIC_LIBS)
+  add_zookeeper_library(zookeeper_st_static st STATIC src/st_adaptor.c)
+  if(WANT_SYNCAPI)
+    add_zookeeper_library(zookeeper_mt_static mt STATIC src/mt_adaptor.c)
+  endif()
+endif()
 
 option(WITH_OPENSSL "turn ON/OFF SSL support, or define openssl library location (default: ON)" ON)
 message("-- using WITH_OPENSSL=${WITH_OPENSSL}")
 if(NOT WITH_OPENSSL STREQUAL "OFF")
   if(NOT WITH_OPENSSL STREQUAL "ON")
-    set(OPENSSL_ROOT_DIR,${WITH_OPENSSL})
+    set(OPENSSL_ROOT_DIR ${WITH_OPENSSL})
   endif()
   find_package(OpenSSL)
   if(OPENSSL_FOUND)
-    target_compile_definitions(zookeeper PUBLIC HAVE_OPENSSL_H)
-    target_link_libraries(zookeeper PUBLIC OpenSSL::SSL OpenSSL::Crypto)
+    foreach(target ${zookeeper_library_targets})
+      target_compile_definitions(${target} PUBLIC HAVE_OPENSSL_H)
+      target_link_libraries(${target} PUBLIC OpenSSL::SSL OpenSSL::Crypto)
+    endforeach()
     message("-- OpenSSL libraries found! will build with SSL support.")
   else()
     message("-- WARNING: unable to find OpenSSL libraries! will build without SSL support.")
@@ -220,22 +276,47 @@ endif()
 
 if(WANT_SYNCAPI AND NOT WIN32)
   find_package(Threads REQUIRED)
-  target_link_libraries(zookeeper PUBLIC Threads::Threads)
+  foreach(target zookeeper_mt_shared zookeeper_mt_static)
+    if(TARGET ${target})
+      target_link_libraries(${target} PUBLIC Threads::Threads)
+    endif()
+  endforeach()
 endif()
 
 if(CYRUS_SASL_FOUND)
-  target_compile_definitions(zookeeper PUBLIC HAVE_CYRUS_SASL_H)
-  target_link_libraries(zookeeper PUBLIC CyrusSASL)
+  foreach(target ${zookeeper_library_targets})
+    target_compile_definitions(${target} PUBLIC HAVE_CYRUS_SASL_H)
+    target_link_libraries(${target} PUBLIC CyrusSASL)
+  endforeach()
 endif()
 
-# cli executable
-add_executable(cli src/cli.c)
-target_link_libraries(cli zookeeper)
+# Command-line clients follow the Autotools layout.  When both library kinds
+# are requested, link the samples against the shared libraries.
+if(TARGET zookeeper_st_shared)
+  set(zookeeper_st_cli_target zookeeper_st_shared)
+else()
+  set(zookeeper_st_cli_target zookeeper_st_static)
+endif()
+add_executable(cli_st src/cli.c)
+target_link_libraries(cli_st ${zookeeper_st_cli_target})
+
+# Multithreaded client and load generator are only available with Sync API.
+if(WANT_SYNCAPI)
+  if(TARGET zookeeper_mt_shared)
+    set(zookeeper_mt_cli_target zookeeper_mt_shared)
+  else()
+    set(zookeeper_mt_cli_target zookeeper_mt_static)
+  endif()
+  add_executable(cli_mt src/cli.c)
+  target_link_libraries(cli_mt ${zookeeper_mt_cli_target})
 
-# load_gen executable
-if(WANT_SYNCAPI AND NOT WIN32)
   add_executable(load_gen src/load_gen.c)
-  target_link_libraries(load_gen zookeeper)
+  target_link_libraries(load_gen ${zookeeper_mt_cli_target})
+  if(WIN32)
+    # winport is an internal part of the client DLL, while load_gen uses its
+    # pthread compatibility helpers directly.
+    target_sources(load_gen PRIVATE src/winport.c)
+  endif()
 endif()
 
 # tests
@@ -273,7 +354,11 @@ if(WANT_CPPUNIT)
   target_compile_definitions(zktest
     PRIVATE -DZKSERVER_CMD="${CMAKE_CURRENT_SOURCE_DIR}/tests/zkServer.sh")
   # TODO: Use `find_library()` for `cppunit`.
-  target_link_libraries(zktest zookeeper cppunit dl)
+  if(WANT_SYNCAPI)
+    target_link_libraries(zktest ${zookeeper_mt_cli_target} cppunit dl)
+  else()
+    target_link_libraries(zktest ${zookeeper_st_cli_target} cppunit dl)
+  endif()
 
   # This reads the link flags from the file `tests/wrappers.opt` into
   # the variable `symbol_wrappers` for use in `target_link_libraries`.
diff --git a/zookeeper-client/zookeeper-client-c/README b/zookeeper-client/zookeeper-client-c/README
index a31c6aa060b..a34824671fe 100644
--- a/zookeeper-client/zookeeper-client-c/README
+++ b/zookeeper-client/zookeeper-client-c/README
@@ -39,6 +39,29 @@ Please refer to the "Installation" item under "C Binding" in the
 Programmer's Guide:
    https://zookeeper.apache.org/doc/current/developer/programmers-guide/bindings#installation
 
+MINGW-W64
+
+The CMake build supports both 32-bit and 64-bit MinGW-w64 toolchains. Before
+configuring, run `mvn -pl zookeeper-jute generate-sources -DskipTests` from the
+ZooKeeper top-level directory to generate the Jute C sources. A typical 64-bit
+cross-build from Linux is:
+
+  cmake -S . -B build-mingw64 \
+    -DCMAKE_SYSTEM_NAME=Windows \
+    -DCMAKE_C_COMPILER=x86_64-w64-mingw32-gcc \
+    -DCMAKE_CXX_COMPILER=x86_64-w64-mingw32-g++ \
+    -DBUILD_SHARED_LIBS=ON \
+    -DWITH_OPENSSL=OFF -DWITH_CYRUS_SASL=OFF
+  cmake --build build-mingw64
+
+Use i686-w64-mingw32-gcc and i686-w64-mingw32-g++ for a 32-bit build. OpenSSL
+and Cyrus SASL can be enabled when MinGW-built versions of those dependencies
+are available to CMake. CMake always builds the single-threaded zookeeper_st
+library and, unless `-DWANT_SYNCAPI=OFF` is used, also builds the multithreaded
+zookeeper_mt library. Set `-DBUILD_STATIC_LIBS=ON` alongside
+`-DBUILD_SHARED_LIBS=ON` to produce both static and shared libraries in one
+build directory.
+
 EXAMPLE/SAMPLE C CLIENT SHELL
 
 NOTE: the ZooKeeper C client shell (cli_st and cli_mt) is meant as a
diff --git a/zookeeper-client/zookeeper-client-c/include/win_getopt.h b/zookeeper-client/zookeeper-client-c/include/win_getopt.h
index c50c7a47140..479efbc30dd 100644
--- a/zookeeper-client/zookeeper-client-c/include/win_getopt.h
+++ b/zookeeper-client/zookeeper-client-c/include/win_getopt.h
@@ -77,7 +77,9 @@
 
 #ifndef __GETOPT_H__
 
-#pragma warning(disable:4996);
+#ifdef _MSC_VER
+#pragma warning(disable:4996)
+#endif
 
 #define __GETOPT_H__
 
@@ -136,6 +138,7 @@ static char EMSG[] = "";
 #define	EMSG		""
 #endif
 
+struct option;
 static int getopt_internal(int, char * const *, const char *,
 			   const struct option *, int *, int);
 static int parse_long_options(char * const *, const char *,
diff --git a/zookeeper-client/zookeeper-client-c/include/winconfig.h b/zookeeper-client/zookeeper-client-c/include/winconfig.h
index c273a932a24..ff3bac52cf6 100644
--- a/zookeeper-client/zookeeper-client-c/include/winconfig.h
+++ b/zookeeper-client/zookeeper-client-c/include/winconfig.h
@@ -1,14 +1,14 @@
 #ifndef WINCONFIG_H_
 #define WINCONFIG_H_
 
-/* Define to `__inline__' or `__inline' if that's what the C compiler
-   calls it, or to nothing if 'inline' is not supported under any name.  */
+/* GCC-compatible attributes and C99 keywords are supported by MinGW. */
+#ifdef _MSC_VER
 #ifndef __cplusplus
 #define inline __inline
 #endif
-
 #define __attribute__(x)
 #define __func__ __FUNCTION__
+#endif
 
 #define ACL ZKACL /* Conflict with windows API */
 
diff --git a/zookeeper-client/zookeeper-client-c/src/addrvec.h b/zookeeper-client/zookeeper-client-c/src/addrvec.h
index 2a9a8ad9117..ee362df1eaf 100644
--- a/zookeeper-client/zookeeper-client-c/src/addrvec.h
+++ b/zookeeper-client/zookeeper-client-c/src/addrvec.h
@@ -25,7 +25,7 @@
 #include <netinet/in.h>
 #include <netdb.h>
 #else
-#include <WinSock2.h>
+#include <winsock2.h>
 #include <stdint.h>
 #endif
 
@@ -135,4 +135,3 @@ int addrvec_eq(const addrvec_t *a1, const addrvec_t *a2);
 #endif // ADDRVEC_H
 
 
-
diff --git a/zookeeper-client/zookeeper-client-c/src/cli.c b/zookeeper-client/zookeeper-client-c/src/cli.c
index c34be8d5961..3934210becc 100644
--- a/zookeeper-client/zookeeper-client-c/src/cli.c
+++ b/zookeeper-client/zookeeper-client-c/src/cli.c
@@ -1054,13 +1054,21 @@ int main(int argc, char **argv) {
     FD_ZERO(&wfds);
     FD_ZERO(&efds);
     while (!shutdownThisThing) {
+#ifdef WIN32
+        SOCKET fd;
+#else
         int fd;
+#endif
         int interest;
         int events;
         struct timeval tv;
         int rc;
         zookeeper_interest(zh, &fd, &interest, &tv);
+#ifdef WIN32
+        if (fd != INVALID_SOCKET) {
+#else
         if (fd != -1) {
+#endif
             if (interest&ZOOKEEPER_READ) {
                 FD_SET(fd, &rfds);
             } else {
diff --git a/zookeeper-client/zookeeper-client-c/src/load_gen.c b/zookeeper-client/zookeeper-client-c/src/load_gen.c
index f25edcbe928..84c7192d1dc 100644
--- a/zookeeper-client/zookeeper-client-c/src/load_gen.c
+++ b/zookeeper-client/zookeeper-client-c/src/load_gen.c
@@ -19,7 +19,9 @@
 #include <zookeeper.h>
 #include "zookeeper_log.h"
 #include <errno.h>
-#ifdef THREADED 
+#ifdef WIN32
+#include "winport.h"
+#else
 #include <pthread.h>
 #endif
 #include <string.h>
@@ -29,11 +31,11 @@ static zhandle_t *zh;
 
 // *****************************************************************************
 //
-static pthread_cond_t cond=PTHREAD_COND_INITIALIZER;
-static pthread_mutex_t lock=PTHREAD_MUTEX_INITIALIZER;
+static pthread_cond_t cond;
+static pthread_mutex_t lock;
 
-static pthread_cond_t counterCond=PTHREAD_COND_INITIALIZER;
-static pthread_mutex_t counterLock=PTHREAD_MUTEX_INITIALIZER;
+static pthread_cond_t counterCond;
+static pthread_mutex_t counterLock;
 static int counter; 
 
 
@@ -230,6 +232,12 @@ void usage(char *argv[]){
 int main(int argc, char **argv) {
     int nodeCount;
     int cleaning=0;
+
+    pthread_mutex_init(&lock, 0);
+    pthread_cond_init(&cond, 0);
+    pthread_mutex_init(&counterLock, 0);
+    pthread_cond_init(&counterCond, 0);
+
     if (argc < 4) {
         usage(argv);
     }
diff --git a/zookeeper-client/zookeeper-client-c/src/mt_adaptor.c b/zookeeper-client/zookeeper-client-c/src/mt_adaptor.c
index 174701c7358..a5c76ae911c 100644
--- a/zookeeper-client/zookeeper-client-c/src/mt_adaptor.c
+++ b/zookeeper-client/zookeeper-client-c/src/mt_adaptor.c
@@ -316,8 +316,13 @@ void adaptor_destroy(zhandle_t *zh)
 
     pthread_mutex_destroy(&zh->auth_h.lock);
 
+#ifdef WIN32
+    closesocket(adaptor->self_pipe[0]);
+    closesocket(adaptor->self_pipe[1]);
+#else
     close(adaptor->self_pipe[0]);
     close(adaptor->self_pipe[1]);
+#endif
     free(adaptor);
     zh->adaptor_priv=0;
 }
@@ -443,7 +448,7 @@ void *do_io(void *v)
             }
         }
         else if (rc < 0) {
-            LOG_ERROR(LOGCALLBACK(zh), ("select() failed %d [%d].", rc, WSAGetLastError()));
+            LOG_ERROR(LOGCALLBACK(zh), "select() failed %d [%d].", rc, WSAGetLastError());
 
             // Clear interest events for zookeeper_process if select() fails.
             interest = 0;
@@ -503,7 +508,7 @@ int32_t fetch_and_add(volatile int32_t* operand, int incr)
 #ifndef WIN32
     return __sync_fetch_and_add(operand, incr);
 #else
-    return InterlockedExchangeAdd(operand, incr);
+    return InterlockedExchangeAdd((volatile LONG *)operand, incr);
 #endif
 }
 
diff --git a/zookeeper-client/zookeeper-client-c/src/winport.c b/zookeeper-client/zookeeper-client-c/src/winport.c
index 8d8698ee6c5..3a9229833e8 100644
--- a/zookeeper-client/zookeeper-client-c/src/winport.c
+++ b/zookeeper-client/zookeeper-client-c/src/winport.c
@@ -73,7 +73,11 @@ pthread_t pthread_self(){
 int pthread_join(pthread_t _thread, void** ignore)
 {
        int rc = WaitForSingleObject( _thread.thread_handle, INFINITE );
-       return ((rc == WAIT_OBJECT_0) ? 0: rc); 
+       if (rc == WAIT_OBJECT_0) {
+           CloseHandle(_thread.thread_handle);
+           return 0;
+       }
+       return rc;
 }
 
 int pthread_detach(pthread_t _thread)
@@ -163,6 +167,8 @@ pthread_cond_broadcast (pthread_cond_t *cv)
   }
   else
     LeaveCriticalSection (&cv->waiters_count_lock_);
+
+  return 0;
 }
 
 
@@ -202,43 +208,29 @@ pthread_cond_wait (pthread_cond_t *cv,
     // Always regain the external mutex since that's the guarantee we
     // give to our callers. 
     WaitForSingleObject (*external_mutex, INFINITE);
+
+  return 0;
 }
 
 int pthread_key_create(pthread_key_t *key, void (*destructor)(void *) )
 {
-  int result = 0;
-  pthread_key_t* newkey;
-
-  if ((newkey = (pthread_key_t*) calloc (1, sizeof (pthread_key_t))) == NULL)
-    {
-      result = ENOMEM;
-    }
-  else if ((newkey->key = TlsAlloc ()) == TLS_OUT_OF_INDEXES)
-    {
-      result = EAGAIN;
-      free (newkey);
-      newkey = NULL;
-    }
-  else if (destructor != NULL)
-    {
-      //--we have to store the function pointer for destructor, so that we can call it 
-         //--to free up the user allocated storage--       
-      newkey->destructor = destructor;
-    }
-  key = newkey;  
-  return (result);     
+  key->key = TlsAlloc();
+  if (key->key == TLS_OUT_OF_INDEXES)
+    return EAGAIN;
+
+  key->destructor = destructor;
+  return 0;
 }
 
 int pthread_key_delete(pthread_key_t key)
 {
-  int rc = 0;
+  int rc;
   LPVOID lpvData =  TlsGetValue(key.key);
-  rc = TlsFree (key.key);
-  rc = (rc != 0 ) ? 0 : GetLastError();
   if (key.destructor != NULL && lpvData != 0){
        key.destructor(lpvData);         //we take control of calling destructor, instead of calling it on thread exit.
   }
-  free (&key);
+  rc = TlsFree (key.key);
+  rc = (rc != 0 ) ? 0 : GetLastError();
   return (rc);
 }
 
@@ -253,7 +245,7 @@ void *pthread_getspecific(pthread_key_t key)
 
 int pthread_setspecific(pthread_key_t key, const void *value)
 {
-       int rc = TlsSetValue (key.key, value);
+       int rc = TlsSetValue (key.key, (LPVOID)value);
        return ((rc != 0 ) ? 0 : GetLastError());
 }
 
@@ -266,10 +258,6 @@ int gettimeofday(struct timeval *tp, void *tzp) {
         return 0;
 }
 
-int close(SOCKET fd) {
-        return closesocket(fd);
-}
-
 int Win32WSAStartup()
 {
        WORD    wVersionRq;
@@ -302,6 +290,3 @@ double drand48(void)
 }
 
 #endif //WIN32
-
-
-
diff --git a/zookeeper-client/zookeeper-client-c/src/winport.h b/zookeeper-client/zookeeper-client-c/src/winport.h
index e8f10ba046b..b60afdf2fd0 100644
--- a/zookeeper-client/zookeeper-client-c/src/winport.h
+++ b/zookeeper-client/zookeeper-client-c/src/winport.h
@@ -31,18 +31,22 @@
 #include <winsock2.h> /* must always be included before ws2tcpip.h */
 #include <ws2tcpip.h> /* for struct sock_addr used in zookeeper.h */
 
-/* POSIX names are deprecated, use ISO conformant names instead. */
+/* POSIX names are deprecated by Microsoft's CRT.  MinGW provides them. */
+#ifdef _MSC_VER
 #define strdup _strdup
 #define getcwd _getcwd
 #define getpid _getpid
 
 /* Windows "secure" versions of POSIX reentrant functions */
 #define strtok_r strtok_s
-#define localtime_r(a,b) localtime_s(b,a)
+#endif
+
+/* MinGW's CRT also exposes localtime_s rather than localtime_r. */
+#define localtime_r(a,b) (localtime_s((b),(a)) == 0 ? (b) : NULL)
 
 /* After this version of MSVC, snprintf became a defined function,
    and so cannot be redefined, nor can #ifndef be used to guard it. */
-#if ((defined(_MSC_VER) && _MSC_VER < 1900) || !defined(_MSC_VER))
+#if defined(_MSC_VER) && _MSC_VER < 1900
 #define snprintf _snprintf
 #endif
 
@@ -54,7 +58,9 @@
 #include <malloc.h>
 
 
+#ifdef _MSC_VER
 typedef int ssize_t;
+#endif
 typedef HANDLE pthread_mutex_t;
 
 struct pthread_t_
@@ -128,7 +134,6 @@ void *pthread_getspecific(pthread_key_t key);
 int pthread_setspecific(pthread_key_t key, const void *value);
 
 int gettimeofday(struct timeval *tp, void *tzp);
-int close(SOCKET fd);
 int Win32WSAStartup();
 void Win32WSACleanup();
 double drand48(void);
diff --git a/zookeeper-client/zookeeper-client-c/src/zk_log.c b/zookeeper-client/zookeeper-client-c/src/zk_log.c
index 79ebd61f18e..dec703ab8c4 100644
--- a/zookeeper-client/zookeeper-client-c/src/zk_log.c
+++ b/zookeeper-client/zookeeper-client-c/src/zk_log.c
@@ -24,8 +24,11 @@
 #ifndef WIN32
 #include <unistd.h>
 #else
+#ifdef _MSC_VER
 typedef DWORD pid_t;
+#endif
 #include <process.h> /* for getpid */
+#include "winport.h"
 #endif
 
 #include <stdarg.h>
@@ -200,4 +203,3 @@ void zoo_set_debug_level(ZooLogLevel level)
     if(level>ZOO_LOG_LEVEL_DEBUG)level=ZOO_LOG_LEVEL_DEBUG;
     logLevel=level;
 }
-
diff --git a/zookeeper-client/zookeeper-client-c/src/zookeeper.c b/zookeeper-client/zookeeper-client-c/src/zookeeper.c
index cdd9d74a537..7dccc583c80 100644
--- a/zookeeper-client/zookeeper-client-c/src/zookeeper.c
+++ b/zookeeper-client/zookeeper-client-c/src/zookeeper.c
@@ -95,11 +95,15 @@
 #endif
 
 #ifdef WIN32
+#include "winport.h"
 #include <process.h> /* for getpid */
 #include <direct.h> /* for getcwd */
 #define EAI_ADDRFAMILY WSAEINVAL /* is this still needed? */
 #define EHOSTDOWN EPIPE
 #define ESTALE ENODEV
+#define ZOO_INVALID_SOCKET INVALID_SOCKET
+#else
+#define ZOO_INVALID_SOCKET -1
 #endif
 
 #define IF_DEBUG(x) if(logLevel==ZOO_LOG_LEVEL_DEBUG) {x;}
@@ -433,7 +437,19 @@ void get_system_time(struct timeval *tv)
 {
   int ret;
 
-#ifdef __MACH__ // OS X
+#ifdef _WIN32
+  LARGE_INTEGER counts, countsPerSecond, countsPerMicrosecond;
+  if (QueryPerformanceFrequency(&countsPerSecond) &&
+      QueryPerformanceCounter(&counts)) {
+    countsPerMicrosecond.QuadPart = countsPerSecond.QuadPart / 1000000;
+    tv->tv_sec = (long)(counts.QuadPart / countsPerSecond.QuadPart);
+    tv->tv_usec = (long)((counts.QuadPart % countsPerSecond.QuadPart) /
+        countsPerMicrosecond.QuadPart);
+    ret = 0;
+  } else {
+    ret = gettimeofday(tv, NULL);
+  }
+#elif defined(__MACH__) // OS X
   clock_serv_t cclock;
   mach_timespec_t mts;
   ret = host_get_clock_service(mach_host_self(), SYSTEM_CLOCK, &cclock);
@@ -462,18 +478,6 @@ void get_system_time(struct timeval *tv)
   ret = clock_gettime(CLOCK_MONOTONIC, &ts);
   tv->tv_sec = ts.tv_sec;
   tv->tv_usec = ts.tv_nsec / 1000;
-#elif _WIN32
-  LARGE_INTEGER counts, countsPerSecond, countsPerMicrosecond;
-  if (QueryPerformanceFrequency(&countsPerSecond) &&
-      QueryPerformanceCounter(&counts)) {
-    countsPerMicrosecond.QuadPart = countsPerSecond.QuadPart / 1000000;
-    tv->tv_sec = (long)(counts.QuadPart / countsPerSecond.QuadPart);
-    tv->tv_usec = (long)((counts.QuadPart % countsPerSecond.QuadPart) /
-        countsPerMicrosecond.QuadPart);
-    ret = 0;
-  } else {
-    ret = gettimeofday(tv, NULL);
-  }
 #else
   ret = gettimeofday(tv, NULL);
 #endif
@@ -646,7 +650,7 @@ zk_hashtable *child_result_checker(zhandle_t *zh, int rc)
 
 void close_zsock(zsock_t *fd)
 {
-    if (fd->sock != -1) {
+    if (fd->sock != ZOO_INVALID_SOCKET) {
 #ifdef HAVE_OPENSSL_H
         if (fd->ssl_sock) {
             SSL_free(fd->ssl_sock);
@@ -655,8 +659,12 @@ void close_zsock(zsock_t *fd)
             fd->ssl_ctx = NULL;
         }
 #endif
+#ifdef _WIN32
+        closesocket(fd->sock);
+#else
         close(fd->sock);
-        fd->sock = -1;
+#endif
+        fd->sock = ZOO_INVALID_SOCKET;
     }
 }
 
@@ -678,7 +686,7 @@ static void destroy(zhandle_t *zh)
         free(zh->hostname);
         zh->hostname = NULL;
     }
-    if (zh->fd->sock != -1) {
+    if (zh->fd->sock != ZOO_INVALID_SOCKET) {
         close_zsock(zh->fd);
         memset(&zh->addr_cur, 0, sizeof(zh->addr_cur));
         zh->state = 0;
@@ -1065,7 +1073,7 @@ int update_addrs(zhandle_t *zh, const struct timeval *ref_time)
     // Check if we are due for a host name resolution.  (See
     // zoo_set_servers_resolution_delay.  The answer is always "yes"
     // if no reference is provided or the file descriptor is invalid.)
-    if (ref_time && zh->fd->sock != -1) {
+    if (ref_time && zh->fd->sock != ZOO_INVALID_SOCKET) {
         int do_resolve;
 
         if (zh->resolve_delay_ms <= 0) {
@@ -1180,7 +1188,7 @@ int update_addrs(zhandle_t *zh, const struct timeval *ref_time)
     // If we need to do a reconfig and we're currently connected to a server,
     // then force close that connection so on next interest() call we'll make a
     // new connection
-    if (zh->reconfig == 1 && zh->fd->sock != -1)
+    if (zh->reconfig == 1 && zh->fd->sock != ZOO_INVALID_SOCKET)
     {
         close_zsock(zh->fd);
         zh->state = ZOO_NOTCONNECTED_STATE;
@@ -1267,8 +1275,14 @@ static void log_env(zhandle_t *zh) {
   LOG_INFO(LOGCALLBACK(zh), "Client environment:os.version=<not implemented>");
 #endif
 
-#ifdef HAVE_GETLOGIN
+#if defined(HAVE_GETLOGIN) && !defined(WIN32)
   LOG_INFO(LOGCALLBACK(zh), "Client environment:user.name=%s", getlogin());
+#elif defined(WIN32)
+  {
+    const char *username = getenv("USERNAME");
+    LOG_INFO(LOGCALLBACK(zh), "Client environment:user.name=%s",
+             username ? username : "<NA>");
+  }
 #else
   LOG_INFO(LOGCALLBACK(zh), "Client environment:user.name=<not implemented>");
 #endif
@@ -1328,7 +1342,7 @@ static zhandle_t *zookeeper_init_internal(const char *host, watcher_fn watcher,
     }
 
     zh->fd = calloc(1, sizeof(zsock_t));
-    zh->fd->sock = -1;
+    zh->fd->sock = ZOO_INVALID_SOCKET;
     if (cert) {
         zh->fd->cert = calloc(1, sizeof(zcert_t));
         memcpy(zh->fd->cert, cert, sizeof(zcert_t));
@@ -2373,7 +2387,7 @@ static int ping_rw_server(zhandle_t* zh)
     sock_flags = SOCK_STREAM;
 #endif
     fd.sock = socket(zh->addr_rw_server.ss_family, sock_flags, 0);
-    if (fd.sock < 0) {
+    if (fd.sock == ZOO_INVALID_SOCKET) {
         return 0;
     }
 
@@ -2440,11 +2454,18 @@ static void zookeeper_set_sock_noblock(zhandle_t *zh, socket_t sock)
 
 static void zookeeper_set_sock_timeout(zhandle_t *zh, socket_t s, int timeout)
 {
+#ifdef _WIN32
+    DWORD timeout_ms = (DWORD)timeout * 1000;
+
+    setsockopt(s, SOL_SOCKET, SO_SNDTIMEO, (const char *)&timeout_ms, sizeof(timeout_ms));
+    setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, (const char *)&timeout_ms, sizeof(timeout_ms));
+#else
     struct timeval tv;
 
     tv.tv_sec = timeout;
     setsockopt(s, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(struct timeval));
     setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(struct timeval));
+#endif
 }
 
 static void zookeeper_set_sock_nodelay(zhandle_t *zh, socket_t sock)
@@ -2551,7 +2572,7 @@ int zookeeper_interest(zhandle_t *zh, socket_t *fd, int *interest,
     tv->tv_sec = 0;
     tv->tv_usec = 0;
 
-    if (*fd == -1) {
+    if (*fd == ZOO_INVALID_SOCKET) {
         /*
          * If we previously failed to connect to server pool (zh->delay == 1)
          * then we need delay our connection on this iteration 1/60 of the
@@ -2578,7 +2599,7 @@ int zookeeper_interest(zhandle_t *zh, socket_t *fd, int *interest,
                 zoo_cycle_next_server(zh);
             }
             zh->fd->sock  = socket(zh->addr_cur.ss_family, sock_flags, 0);
-            if (zh->fd->sock < 0) {
+            if (zh->fd->sock == ZOO_INVALID_SOCKET) {
               rc = handle_socket_error_msg(zh,
                                            __LINE__,
                                            __func__,
@@ -2638,7 +2659,7 @@ int zookeeper_interest(zhandle_t *zh, socket_t *fd, int *interest,
         zh->ping_rw_timeout = MIN_RW_TIMEOUT;
     }
 
-    if (zh->fd->sock != -1) {
+    if (zh->fd->sock != ZOO_INVALID_SOCKET) {
         int idle_recv = calculate_interval(&zh->last_recv, &now);
         int idle_send = calculate_interval(&zh->last_send, &now);
         int recv_to = zh->recv_timeout*2/3 - idle_recv;
@@ -2955,14 +2976,20 @@ static int process_sasl_response(zhandle_t *zh, char *buffer, int len)
 
 static int check_events(zhandle_t *zh, int events)
 {
-    if (zh->fd->sock == -1)
+    if (zh->fd->sock == ZOO_INVALID_SOCKET)
         return ZINVALIDSTATE;
 
 #ifdef HAVE_OPENSSL_H
     if ((events&ZOOKEEPER_WRITE) && (zh->state == ZOO_SSL_CONNECTING_STATE) && zh->fd->cert != NULL) {
         int rc, error;
         socklen_t len = sizeof(error);
-        rc = getsockopt(zh->fd->sock, SOL_SOCKET, SO_ERROR, &error, &len);
+        rc = getsockopt(zh->fd->sock, SOL_SOCKET, SO_ERROR,
+#ifdef _WIN32
+                        (char *)&error,
+#else
+                        &error,
+#endif
+                        &len);
         /* the description in section 16.4 "Non-blocking connect"
          * in UNIX Network Programming vol 1, 3rd edition, points out
          * that sometimes the error is in errno and sometimes in error */
@@ -2982,7 +3009,13 @@ static int check_events(zhandle_t *zh, int events)
     if ((events&ZOOKEEPER_WRITE)&&(zh->state == ZOO_CONNECTING_STATE)) {
         int rc, error;
         socklen_t len = sizeof(error);
-        rc = getsockopt(zh->fd->sock, SOL_SOCKET, SO_ERROR, &error, &len);
+        rc = getsockopt(zh->fd->sock, SOL_SOCKET, SO_ERROR,
+#ifdef _WIN32
+                        (char *)&error,
+#else
+                        &error,
+#endif
+                        &len);
         /* the description in section 16.4 "Non-blocking connect"
          * in UNIX Network Programming vol 1, 3rd edition, points out
          * that sometimes the error is in errno and sometimes in error */
@@ -3379,7 +3412,7 @@ static void isSocketReadable(zhandle_t* zh)
     fd_set rfds;
     struct timeval waittime = {0, 0};
     FD_ZERO(&rfds);
-    FD_SET( zh->fd , &rfds);
+    FD_SET(zh->fd->sock, &rfds);
     if (select(0, &rfds, NULL, NULL, &waittime) <= 0){
         // socket not readable -- no more responses to process
         zh->socket_readable.tv_sec=zh->socket_readable.tv_usec=0;
@@ -3986,7 +4019,7 @@ static int Request_path_watch_init(zhandle_t *zh, int mode,
 static int nonblocking_send(zhandle_t *zh, int rc)
 {
     if (adaptor_send_queue(zh, 0) < 0) {
-        if (zh->fd->sock != -1) {
+        if (zh->fd->sock != ZOO_INVALID_SOCKET) {
             close_zsock(zh->fd);
             zh->state = ZOO_NOTCONNECTED_STATE;
         }
@@ -5136,7 +5169,9 @@ static const char* format_endpoint_info(const struct sockaddr_storage* ep)
 #else
     static __thread char buf[134] = { 0 };
 #endif
+#ifndef _WIN32
     char addrstr[INET6_ADDRSTRLEN] = { 0 };
+#endif
     const char *fmtstring;
     void *inaddr;
     char is_inet6 = 0; // poor man's boolean