diff --git a/Source/kwsys/ProcessWin32.c b/Source/kwsys/ProcessWin32.c
index 26ec57d33e..07e19cdb2e 100644
--- a/Source/kwsys/ProcessWin32.c
+++ b/Source/kwsys/ProcessWin32.c
@@ -1706,16 +1706,17 @@ DWORD kwsysProcessCreate(kwsysProcess* cp, int index,
   }
 
   /* Create inherited copies of the handles.  */
-  (error = kwsysProcessCreateChildHandle(&si->StartupInfo.hStdInput,
-                                         si->hStdInput, 1)) ||
-    (error = kwsysProcessCreateChildHandle(&si->StartupInfo.hStdOutput,
-                                           si->hStdOutput, 0)) ||
-    (error = kwsysProcessCreateChildHandle(&si->StartupInfo.hStdError,
-                                           si->hStdError, 0)) ||
-    /* Create the process.  */
-    (!CreateProcessW(0, cp->Commands[index], 0, 0, TRUE, creationFlags, 0, 0,
-                     &si->StartupInfo, &cp->ProcessInformation[index]) &&
-     (error = GetLastError()));
+  (void)((error = kwsysProcessCreateChildHandle(&si->StartupInfo.hStdInput,
+                                                si->hStdInput, 1)) ||
+         (error = kwsysProcessCreateChildHandle(&si->StartupInfo.hStdOutput,
+                                                si->hStdOutput, 0)) ||
+         (error = kwsysProcessCreateChildHandle(&si->StartupInfo.hStdError,
+                                                si->hStdError, 0)) ||
+         /* Create the process.  */
+         (!CreateProcessW(0, cp->Commands[index], 0, 0, TRUE, creationFlags, 0,
+                          0, &si->StartupInfo,
+                          &cp->ProcessInformation[index]) &&
+          (error = GetLastError())));
 
   /* Close the inherited copies of the handles. */
   if (si->StartupInfo.hStdInput != si->hStdInput) {
@@ -2354,7 +2355,7 @@ static int kwsysProcess_List__New_NT4(kwsysProcess_List* self)
   if (hNT) {
     /* Get pointers to the needed API functions.  */
     self->P_ZwQuerySystemInformation =
-      ((ZwQuerySystemInformationType)GetProcAddress(
+      ((ZwQuerySystemInformationType)(void*)GetProcAddress(
         hNT, "ZwQuerySystemInformation"));
   }
   if (!self->P_ZwQuerySystemInformation) {
@@ -2418,12 +2419,13 @@ static int kwsysProcess_List__Next_NT4(kwsysProcess_List* self)
 
 static int kwsysProcess_List__GetProcessId_NT4(kwsysProcess_List* self)
 {
-  return self->CurrentInfo ? self->CurrentInfo->ProcessId : -1;
+  return self->CurrentInfo ? (int)self->CurrentInfo->ProcessId : -1;
 }
 
 static int kwsysProcess_List__GetParentId_NT4(kwsysProcess_List* self)
 {
-  return self->CurrentInfo ? self->CurrentInfo->InheritedFromProcessId : -1;
+  return self->CurrentInfo ? (int)self->CurrentInfo->InheritedFromProcessId
+                           : -1;
 }
 
 static int kwsysProcess_List__New_Snapshot(kwsysProcess_List* self)
@@ -2435,12 +2437,12 @@ static int kwsysProcess_List__New_Snapshot(kwsysProcess_List* self)
   HMODULE hKernel = GetModuleHandleW(L"kernel32.dll");
   if (hKernel) {
     self->P_CreateToolhelp32Snapshot =
-      ((CreateToolhelp32SnapshotType)GetProcAddress(
+      ((CreateToolhelp32SnapshotType)(void*)GetProcAddress(
         hKernel, "CreateToolhelp32Snapshot"));
     self->P_Process32First =
-      ((Process32FirstType)GetProcAddress(hKernel, "Process32First"));
+      ((Process32FirstType)(void*)GetProcAddress(hKernel, "Process32First"));
     self->P_Process32Next =
-      ((Process32NextType)GetProcAddress(hKernel, "Process32Next"));
+      ((Process32NextType)(void*)GetProcAddress(hKernel, "Process32Next"));
   }
   return (self->P_CreateToolhelp32Snapshot && self->P_Process32First &&
           self->P_Process32Next)
@@ -2488,12 +2490,12 @@ static int kwsysProcess_List__Next_Snapshot(kwsysProcess_List* self)
 
 static int kwsysProcess_List__GetProcessId_Snapshot(kwsysProcess_List* self)
 {
-  return self->Snapshot ? self->CurrentEntry.th32ProcessID : -1;
+  return self->Snapshot ? (int)self->CurrentEntry.th32ProcessID : -1;
 }
 
 static int kwsysProcess_List__GetParentId_Snapshot(kwsysProcess_List* self)
 {
-  return self->Snapshot ? self->CurrentEntry.th32ParentProcessID : -1;
+  return self->Snapshot ? (int)self->CurrentEntry.th32ParentProcessID : -1;
 }
 
 static void kwsysProcessKill(DWORD pid)
diff --git a/Source/kwsys/Status.cxx b/Source/kwsys/Status.cxx
index 1c343bceed..4cadd8f09e 100644
--- a/Source/kwsys/Status.cxx
+++ b/Source/kwsys/Status.cxx
@@ -46,7 +46,7 @@ std::string Status::GetString() const
 #ifdef _WIN32
     case Kind::Windows: {
       LPWSTR message = NULL;
-      DWORD size = FormatMessageW(
+      FormatMessageW(
         FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
           FORMAT_MESSAGE_IGNORE_INSERTS,
         NULL, this->Windows_, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
diff --git a/Source/kwsys/SystemInformation.cxx b/Source/kwsys/SystemInformation.cxx
index 80766dd6dd..743c224437 100644
--- a/Source/kwsys/SystemInformation.cxx
+++ b/Source/kwsys/SystemInformation.cxx
@@ -3919,8 +3919,8 @@ double SystemInformationImplementation::GetLoadAverage()
   // Old windows.h headers do not provide GetSystemTimes.
   using GetSystemTimesType = BOOL(WINAPI*)(LPFILETIME, LPFILETIME, LPFILETIME);
   static GetSystemTimesType pGetSystemTimes =
-    (GetSystemTimesType)GetProcAddress(GetModuleHandleW(L"kernel32"),
-                                       "GetSystemTimes");
+    (GetSystemTimesType)(void*)GetProcAddress(GetModuleHandleW(L"kernel32"),
+                                              "GetSystemTimes");
   FILETIME idleTime, kernelTime, userTime;
   if (pGetSystemTimes && pGetSystemTimes(&idleTime, &kernelTime, &userTime)) {
     unsigned __int64 const idleTicks = fileTimeToUInt64(idleTime);
@@ -4469,7 +4469,7 @@ void SystemInformationImplementation::CPUCountWindows()
   using GetLogicalProcessorInformationType =
     BOOL(WINAPI*)(PSYSTEM_LOGICAL_PROCESSOR_INFORMATION, PDWORD);
   static GetLogicalProcessorInformationType pGetLogicalProcessorInformation =
-    reinterpret_cast<GetLogicalProcessorInformationType>(GetProcAddress(
+    reinterpret_cast<GetLogicalProcessorInformationType>((void*)GetProcAddress(
       GetModuleHandleW(L"kernel32"), "GetLogicalProcessorInformation"));
 
   if (!pGetLogicalProcessorInformation) {
@@ -5330,7 +5330,8 @@ bool SystemInformationImplementation::QueryOSInformation()
 
   this->OSName = "Windows";
 
-  OSVERSIONINFOEXW osvi = { sizeof(osvi) };
+  OSVERSIONINFOEXW osvi = {};
+  osvi.dwOSVersionInfoSize = sizeof(osvi);
 #  ifdef KWSYS_WINDOWS_DEPRECATED_GetVersionEx
 #    pragma warning(push)
 #    ifdef __INTEL_COMPILER
diff --git a/Source/kwsys/testProcess.c b/Source/kwsys/testProcess.c
index 3c61ada87c..1ab746b7a1 100644
--- a/Source/kwsys/testProcess.c
+++ b/Source/kwsys/testProcess.c
@@ -133,9 +133,16 @@ static int test4(int argc, char const* argv[])
 #ifdef CRASH_USING_ABORT
   abort();
 #else
+#  if defined(__GNUC__) || defined(__clang__)
+#    pragma GCC diagnostic push
+#    pragma GCC diagnostic ignored "-Warray-bounds"
+#  endif
   assert(invalidAddress); /* Quiet Clang scan-build. */
   /* Provoke deliberate crash by writing to the invalid address. */
   *invalidAddress = 0;
+#  if defined(__GNUC__) || defined(__clang__)
+#    pragma GCC diagnostic pop
+#  endif
 #endif
   fprintf(stdout, "Output after crash on stdout from crash test.\n");
   fprintf(stderr, "Output after crash on stderr from crash test.\n");