diff --git a/Source/CTest/cmCTestRunTest.cxx b/Source/CTest/cmCTestRunTest.cxx
index 7f081ef..5183c6f 100644
--- a/Source/CTest/cmCTestRunTest.cxx
+++ b/Source/CTest/cmCTestRunTest.cxx
@@ -14,6 +14,7 @@
 #include "cmsys/RegularExpression.hxx"
 #include <chrono>
 #include <cmAlgorithms.h>
+#include <cstdint>
 #include <cstring>
 #include <iomanip>
 #include <ratio>
@@ -143,7 +144,7 @@
   if (res != cmProcess::State::Expired) {
     this->TimeoutIsForStopTime = false;
   }
-  int retVal = this->TestProcess->GetExitValue();
+  std::int64_t retVal = this->TestProcess->GetExitValue();
   bool forceFail = false;
   bool skipped = false;
   bool outputTestErrorsToConsole = false;
diff --git a/Source/CTest/cmCTestTestHandler.h b/Source/CTest/cmCTestTestHandler.h
index 0b557db..17d5f3f 100644
--- a/Source/CTest/cmCTestTestHandler.h
+++ b/Source/CTest/cmCTestTestHandler.h
@@ -11,6 +11,7 @@
 
 #include "cmsys/RegularExpression.hxx"
 #include <chrono>
+#include <cstdint>
 #include <iosfwd>
 #include <map>
 #include <set>
@@ -153,7 +154,7 @@
     std::string Reason;
     std::string FullCommandLine;
     cmDuration ExecutionTime;
-    int ReturnValue;
+    std::int64_t ReturnValue;
     int Status;
     std::string ExceptionStatus;
     bool CompressOutput;
diff --git a/Source/CTest/cmProcess.cxx b/Source/CTest/cmProcess.cxx
index c03d004..cd2e2f7 100644
--- a/Source/CTest/cmProcess.cxx
+++ b/Source/CTest/cmProcess.cxx
@@ -11,7 +11,9 @@
 #include <iostream>
 #include <signal.h>
 #include <string>
-#if !defined(_WIN32)
+#if defined(_WIN32)
+#  include "cm_kwiml.h"
+#else
 #  include <unistd.h>
 #endif
 #include <utility>
@@ -353,7 +355,7 @@
   }
 
   // Record exit information.
-  this->ExitValue = static_cast<int>(exit_status);
+  this->ExitValue = exit_status;
   this->Signal = term_signal;
   this->TotalTime = std::chrono::steady_clock::now() - this->StartTime;
   // Because of a processor clock scew the runtime may become slightly
@@ -539,7 +541,8 @@
     case STATUS_NO_MEMORY:
     default:
       char buf[1024];
-      _snprintf(buf, 1024, "Exit code 0x%x\n", this->ExitValue);
+      const char* fmt = "Exit code 0x%" KWIML_INT_PRIx64 "\n";
+      _snprintf(buf, 1024, fmt, this->ExitValue);
       exception_str.assign(buf);
   }
 #else
diff --git a/Source/CTest/cmProcess.h b/Source/CTest/cmProcess.h
index b2d87fa..e5ca17f 100644
--- a/Source/CTest/cmProcess.h
+++ b/Source/CTest/cmProcess.h
@@ -53,7 +53,7 @@
   State GetProcessStatus();
   int GetId() { return this->Id; }
   void SetId(int id) { this->Id = id; }
-  int GetExitValue() { return this->ExitValue; }
+  int64_t GetExitValue() { return this->ExitValue; }
   cmDuration GetTotalTime() { return this->TotalTime; }
 
   enum class Exception
@@ -122,7 +122,7 @@
   std::vector<std::string> Arguments;
   std::vector<const char*> ProcessArgs;
   int Id;
-  int ExitValue;
+  int64_t ExitValue;
 };
 
 #endif