Modernize: Use #pragma once in all header files

#pragma once is a widely supported compiler pragma, even though it is
not part of the C++ standard. Many of the issues keeping #pragma once
from being standardized (distributed filesystems, build farms, hard
links, etc.) do not apply to CMake - it is easy to build CMake on a
single machine. CMake also does not install any header files which can
be consumed by other projects (though cmCPluginAPI.h has been
deliberately omitted from this conversion in case anyone is still using
it.) Finally, #pragma once has been required to build CMake since at
least August 2017 (7f29bbe6 enabled server mode unconditionally, which
had been using #pragma once since September 2016 (b13d3e0d)). The fact
that we now require C++11 filters out old compilers, and it is unlikely
that there is a compiler which supports C++11 but does not support
#pragma once.

51 files changed, 51 insertions, 202 deletions

diff --git a/Source/CTest/cmCTestBZR.h b/Source/CTest/cmCTestBZR.h
index d7c6321281..eb0dbbef81 100644
--- a/Source/CTest/cmCTestBZR.h
+++ b/Source/CTest/cmCTestBZR.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestBZR_h
-#define cmCTestBZR_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -50,5 +49,3 @@ private:
   friend class UpdateParser;
   friend class StatusParser;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestBinPacker.h b/Source/CTest/cmCTestBinPacker.h
index ff02b8565c..e56a4379ad 100644
--- a/Source/CTest/cmCTestBinPacker.h
+++ b/Source/CTest/cmCTestBinPacker.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestBinPacker_h
-#define cmCTestBinPacker_h
+#pragma once
 
 #include <cstddef>
 #include <map>
@@ -27,5 +26,3 @@ bool cmAllocateCTestResourcesRoundRobin(
 bool cmAllocateCTestResourcesBlock(
   const std::map<std::string, cmCTestResourceAllocator::Resource>& resources,
   std::vector<cmCTestBinPackerAllocation>& allocations);
-
-#endif
diff --git a/Source/CTest/cmCTestBuildAndTestHandler.h b/Source/CTest/cmCTestBuildAndTestHandler.h
index 0c8a040793..b9cc35ccbd 100644
--- a/Source/CTest/cmCTestBuildAndTestHandler.h
+++ b/Source/CTest/cmCTestBuildAndTestHandler.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestBuildAndTestHandler_h
-#define cmCTestBuildAndTestHandler_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -71,5 +70,3 @@ protected:
   bool BuildNoCMake;
   cmDuration Timeout;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestBuildCommand.h b/Source/CTest/cmCTestBuildCommand.h
index 0f82817589..00dbcc451b 100644
--- a/Source/CTest/cmCTestBuildCommand.h
+++ b/Source/CTest/cmCTestBuildCommand.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestBuildCommand_h
-#define cmCTestBuildCommand_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -62,5 +61,3 @@ protected:
   std::string Flags;
   std::string ProjectName;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestBuildHandler.h b/Source/CTest/cmCTestBuildHandler.h
index a5193f6e55..58e8d9cbb1 100644
--- a/Source/CTest/cmCTestBuildHandler.h
+++ b/Source/CTest/cmCTestBuildHandler.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestBuildHandler_h
-#define cmCTestBuildHandler_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -156,5 +155,3 @@ private:
   friend class LaunchHelper;
   class FragmentCompare;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestCVS.h b/Source/CTest/cmCTestCVS.h
index 7d33d8f2de..d20239b037 100644
--- a/Source/CTest/cmCTestCVS.h
+++ b/Source/CTest/cmCTestCVS.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestCVS_h
-#define cmCTestCVS_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -51,5 +50,3 @@ private:
   friend class LogParser;
   friend class UpdateParser;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestCommand.h b/Source/CTest/cmCTestCommand.h
index 8efb4194c9..007378dc2e 100644
--- a/Source/CTest/cmCTestCommand.h
+++ b/Source/CTest/cmCTestCommand.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestCommand_h
-#define cmCTestCommand_h
+#pragma once
 
 #include "cmCommand.h"
 
@@ -27,5 +26,3 @@ public:
   cmCTest* CTest;
   cmCTestScriptHandler* CTestScriptHandler;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestConfigureCommand.h b/Source/CTest/cmCTestConfigureCommand.h
index 3f5944af60..f338637eef 100644
--- a/Source/CTest/cmCTestConfigureCommand.h
+++ b/Source/CTest/cmCTestConfigureCommand.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestConfigureCommand_h
-#define cmCTestConfigureCommand_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -45,5 +44,3 @@ protected:
 
   std::string Options;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestConfigureHandler.h b/Source/CTest/cmCTestConfigureHandler.h
index 01fe8011e6..2aad98c83d 100644
--- a/Source/CTest/cmCTestConfigureHandler.h
+++ b/Source/CTest/cmCTestConfigureHandler.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestConfigureHandler_h
-#define cmCTestConfigureHandler_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -25,5 +24,3 @@ public:
 
   void Initialize() override;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestCoverageCommand.h b/Source/CTest/cmCTestCoverageCommand.h
index 76aaf46f81..93448529ac 100644
--- a/Source/CTest/cmCTestCoverageCommand.h
+++ b/Source/CTest/cmCTestCoverageCommand.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestCoverageCommand_h
-#define cmCTestCoverageCommand_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -48,5 +47,3 @@ protected:
   bool LabelsMentioned;
   std::vector<std::string> Labels;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestCoverageHandler.h b/Source/CTest/cmCTestCoverageHandler.h
index 991b89d7ba..8732723bc4 100644
--- a/Source/CTest/cmCTestCoverageHandler.h
+++ b/Source/CTest/cmCTestCoverageHandler.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestCoverageHandler_h
-#define cmCTestCoverageHandler_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -149,5 +148,3 @@ private:
   bool IntersectsFilter(LabelSet const& labels);
   bool IsFilteredOut(std::string const& source);
 };
-
-#endif
diff --git a/Source/CTest/cmCTestCurl.h b/Source/CTest/cmCTestCurl.h
index b0d7f0757e..d9aa916807 100644
--- a/Source/CTest/cmCTestCurl.h
+++ b/Source/CTest/cmCTestCurl.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestCurl_h
-#define cmCTestCurl_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -52,5 +51,3 @@ private:
   bool Quiet;
   int TimeOutSeconds;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestEmptyBinaryDirectoryCommand.h b/Source/CTest/cmCTestEmptyBinaryDirectoryCommand.h
index ac96a4e30e..ba2b0ebbd3 100644
--- a/Source/CTest/cmCTestEmptyBinaryDirectoryCommand.h
+++ b/Source/CTest/cmCTestEmptyBinaryDirectoryCommand.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestEmptyBinaryDirectoryCommand_h
-#define cmCTestEmptyBinaryDirectoryCommand_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -45,5 +44,3 @@ public:
   bool InitialPass(std::vector<std::string> const& args,
                    cmExecutionStatus& status) override;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestGIT.h b/Source/CTest/cmCTestGIT.h
index 3103d8492b..a15aef53e3 100644
--- a/Source/CTest/cmCTestGIT.h
+++ b/Source/CTest/cmCTestGIT.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestGIT_h
-#define cmCTestGIT_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -53,5 +52,3 @@ public:
   friend class DiffParser;
   friend class OneLineParser;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestGenericHandler.h b/Source/CTest/cmCTestGenericHandler.h
index 94e5418650..591d9cda9f 100644
--- a/Source/CTest/cmCTestGenericHandler.h
+++ b/Source/CTest/cmCTestGenericHandler.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestGenericHandler_h
-#define cmCTestGenericHandler_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -105,5 +104,3 @@ protected:
   cmCTestCommand* Command;
   int SubmitIndex;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestGlobalVC.h b/Source/CTest/cmCTestGlobalVC.h
index ff86591eae..679b0e19bf 100644
--- a/Source/CTest/cmCTestGlobalVC.h
+++ b/Source/CTest/cmCTestGlobalVC.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestGlobalVC_h
-#define cmCTestGlobalVC_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -73,5 +72,3 @@ protected:
   void WriteXMLDirectory(cmXMLWriter& xml, std::string const& path,
                          Directory const& dir);
 };
-
-#endif
diff --git a/Source/CTest/cmCTestHG.h b/Source/CTest/cmCTestHG.h
index 2900139b4a..b81f0424fb 100644
--- a/Source/CTest/cmCTestHG.h
+++ b/Source/CTest/cmCTestHG.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestHG_h
-#define cmCTestHG_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -42,5 +41,3 @@ private:
   friend class LogParser;
   friend class StatusParser;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestHandlerCommand.h b/Source/CTest/cmCTestHandlerCommand.h
index a20d607e2f..756952d8ec 100644
--- a/Source/CTest/cmCTestHandlerCommand.h
+++ b/Source/CTest/cmCTestHandlerCommand.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestHandlerCommand_h
-#define cmCTestHandlerCommand_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -58,5 +57,3 @@ protected:
   "The APPEND option marks results for append to those previously "           \
   "submitted to a dashboard server since the last ctest_start.  "             \
   "Append semantics are defined by the dashboard server in use."
-
-#endif
diff --git a/Source/CTest/cmCTestLaunch.h b/Source/CTest/cmCTestLaunch.h
index 79a7712aa5..33ff82cd54 100644
--- a/Source/CTest/cmCTestLaunch.h
+++ b/Source/CTest/cmCTestLaunch.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestLaunch_h
-#define cmCTestLaunch_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -103,5 +102,3 @@ private:
   void LoadConfig();
   std::string SourceDir;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestMemCheckCommand.h b/Source/CTest/cmCTestMemCheckCommand.h
index 8f4ffb89a4..6544f16cfd 100644
--- a/Source/CTest/cmCTestMemCheckCommand.h
+++ b/Source/CTest/cmCTestMemCheckCommand.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestMemCheckCommand_h
-#define cmCTestMemCheckCommand_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -43,5 +42,3 @@ protected:
 
   std::string DefectCount;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestMemCheckHandler.h b/Source/CTest/cmCTestMemCheckHandler.h
index 63ab573258..6ef5d20c85 100644
--- a/Source/CTest/cmCTestMemCheckHandler.h
+++ b/Source/CTest/cmCTestMemCheckHandler.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestMemCheckHandler_h
-#define cmCTestMemCheckHandler_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -157,5 +156,3 @@ private:
   //! generate the output filename for the given test index
   void TestOutputFileNames(int test, std::vector<std::string>& files);
 };
-
-#endif
diff --git a/Source/CTest/cmCTestMultiProcessHandler.h b/Source/CTest/cmCTestMultiProcessHandler.h
index e21b912c7c..5de42f9e32 100644
--- a/Source/CTest/cmCTestMultiProcessHandler.h
+++ b/Source/CTest/cmCTestMultiProcessHandler.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestMultiProcessHandler_h
-#define cmCTestMultiProcessHandler_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -200,5 +199,3 @@ protected:
   bool Quiet;
   bool SerialTestRunning;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestP4.h b/Source/CTest/cmCTestP4.h
index e19472ee89..d03f9cbae3 100644
--- a/Source/CTest/cmCTestP4.h
+++ b/Source/CTest/cmCTestP4.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestP4_h
-#define cmCTestP4_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -72,5 +71,3 @@ private:
   friend class DescribeParser;
   friend class DiffParser;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestReadCustomFilesCommand.h b/Source/CTest/cmCTestReadCustomFilesCommand.h
index cbb939030b..03714f6fb6 100644
--- a/Source/CTest/cmCTestReadCustomFilesCommand.h
+++ b/Source/CTest/cmCTestReadCustomFilesCommand.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestReadCustomFilesCommand_h
-#define cmCTestReadCustomFilesCommand_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -44,5 +43,3 @@ public:
   bool InitialPass(std::vector<std::string> const& args,
                    cmExecutionStatus& status) override;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestResourceAllocator.h b/Source/CTest/cmCTestResourceAllocator.h
index 9f0b9c95a3..129e64e5e1 100644
--- a/Source/CTest/cmCTestResourceAllocator.h
+++ b/Source/CTest/cmCTestResourceAllocator.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestResourceAllocator_h
-#define cmCTestResourceAllocator_h
+#pragma once
 
 #include <map>
 #include <string>
@@ -35,5 +34,3 @@ public:
 private:
   std::map<std::string, std::map<std::string, Resource>> Resources;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestResourceGroupsLexerHelper.h b/Source/CTest/cmCTestResourceGroupsLexerHelper.h
index 2cb6cb1c58..ae4fa994d2 100644
--- a/Source/CTest/cmCTestResourceGroupsLexerHelper.h
+++ b/Source/CTest/cmCTestResourceGroupsLexerHelper.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestResourceGroupsLexerHelper_h
-#define cmCTestResourceGroupsLexerHelper_h
+#pragma once
 
 #include <string>
 #include <vector>
@@ -40,5 +39,3 @@ private:
 };
 
 #define YY_EXTRA_TYPE cmCTestResourceGroupsLexerHelper*
-
-#endif
diff --git a/Source/CTest/cmCTestResourceSpec.h b/Source/CTest/cmCTestResourceSpec.h
index cb242c0507..1aa279beff 100644
--- a/Source/CTest/cmCTestResourceSpec.h
+++ b/Source/CTest/cmCTestResourceSpec.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestResourceSpec_h
-#define cmCTestResourceSpec_h
+#pragma once
 
 #include <map>
 #include <string>
@@ -51,5 +50,3 @@ public:
   bool operator==(const cmCTestResourceSpec& other) const;
   bool operator!=(const cmCTestResourceSpec& other) const;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestRunScriptCommand.h b/Source/CTest/cmCTestRunScriptCommand.h
index 2d8bde19df..510b748631 100644
--- a/Source/CTest/cmCTestRunScriptCommand.h
+++ b/Source/CTest/cmCTestRunScriptCommand.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestRunScriptCommand_h
-#define cmCTestRunScriptCommand_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -45,5 +44,3 @@ public:
   bool InitialPass(std::vector<std::string> const& args,
                    cmExecutionStatus& status) override;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestRunTest.h b/Source/CTest/cmCTestRunTest.h
index d831247e1f..863ac1bfdf 100644
--- a/Source/CTest/cmCTestRunTest.h
+++ b/Source/CTest/cmCTestRunTest.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestRunTest_h
-#define cmCTestRunTest_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -159,5 +158,3 @@ inline int getNumWidth(size_t n)
   }
   return w;
 }
-
-#endif
diff --git a/Source/CTest/cmCTestSVN.h b/Source/CTest/cmCTestSVN.h
index b74dc12b0d..370d17682e 100644
--- a/Source/CTest/cmCTestSVN.h
+++ b/Source/CTest/cmCTestSVN.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestSVN_h
-#define cmCTestSVN_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -103,5 +102,3 @@ private:
   friend class UpdateParser;
   friend class ExternalParser;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestScriptHandler.h b/Source/CTest/cmCTestScriptHandler.h
index ebb79055ff..8eb96582bb 100644
--- a/Source/CTest/cmCTestScriptHandler.h
+++ b/Source/CTest/cmCTestScriptHandler.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestScriptHandler_h
-#define cmCTestScriptHandler_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -176,5 +175,3 @@ private:
   std::unique_ptr<cmGlobalGenerator> GlobalGenerator;
   std::unique_ptr<cmake> CMake;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestSleepCommand.h b/Source/CTest/cmCTestSleepCommand.h
index 1c3b8a1e1d..94255761d0 100644
--- a/Source/CTest/cmCTestSleepCommand.h
+++ b/Source/CTest/cmCTestSleepCommand.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestSleepCommand_h
-#define cmCTestSleepCommand_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -45,5 +44,3 @@ public:
   bool InitialPass(std::vector<std::string> const& args,
                    cmExecutionStatus& status) override;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestStartCommand.h b/Source/CTest/cmCTestStartCommand.h
index b30b1bb445..b3d06a729a 100644
--- a/Source/CTest/cmCTestStartCommand.h
+++ b/Source/CTest/cmCTestStartCommand.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestStartCommand_h
-#define cmCTestStartCommand_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -62,5 +61,3 @@ private:
   bool CreateNewTag;
   bool Quiet;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestSubmitCommand.h b/Source/CTest/cmCTestSubmitCommand.h
index 90607713b1..c5d11dfd8b 100644
--- a/Source/CTest/cmCTestSubmitCommand.h
+++ b/Source/CTest/cmCTestSubmitCommand.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestSubmitCommand_h
-#define cmCTestSubmitCommand_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -55,5 +54,3 @@ protected:
   std::vector<std::string> HttpHeaders;
   std::vector<std::string> Parts;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestSubmitHandler.h b/Source/CTest/cmCTestSubmitHandler.h
index 304daaa980..809c6157bd 100644
--- a/Source/CTest/cmCTestSubmitHandler.h
+++ b/Source/CTest/cmCTestSubmitHandler.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestSubmitHandler_h
-#define cmCTestSubmitHandler_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -77,5 +76,3 @@ private:
   std::set<std::string> Files;
   std::vector<std::string> HttpHeaders;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestTestCommand.h b/Source/CTest/cmCTestTestCommand.h
index 7925586792..624cd91fef 100644
--- a/Source/CTest/cmCTestTestCommand.h
+++ b/Source/CTest/cmCTestTestCommand.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestTestCommand_h
-#define cmCTestTestCommand_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -62,5 +61,3 @@ protected:
   std::string ResourceSpecFile;
   bool StopOnFailure = false;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestTestHandler.h b/Source/CTest/cmCTestTestHandler.h
index f9e9391b92..aa29eeb019 100644
--- a/Source/CTest/cmCTestTestHandler.h
+++ b/Source/CTest/cmCTestTestHandler.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestTestHandler_h
-#define cmCTestTestHandler_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -360,5 +359,3 @@ private:
   int RepeatCount = 1;
   bool RerunFailed;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestUpdateCommand.h b/Source/CTest/cmCTestUpdateCommand.h
index 5555c16377..e4c34536f1 100644
--- a/Source/CTest/cmCTestUpdateCommand.h
+++ b/Source/CTest/cmCTestUpdateCommand.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestUpdateCommand_h
-#define cmCTestUpdateCommand_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -42,5 +41,3 @@ public:
 protected:
   cmCTestGenericHandler* InitializeHandler() override;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestUpdateHandler.h b/Source/CTest/cmCTestUpdateHandler.h
index afc0e3d808..25bbb2f5cf 100644
--- a/Source/CTest/cmCTestUpdateHandler.h
+++ b/Source/CTest/cmCTestUpdateHandler.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestUpdateHandler_h
-#define cmCTestUpdateHandler_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -63,5 +62,3 @@ private:
   int DetectVCS(const char* dir);
   bool SelectVCS();
 };
-
-#endif
diff --git a/Source/CTest/cmCTestUploadCommand.h b/Source/CTest/cmCTestUploadCommand.h
index 8334a9e08d..fe155f670f 100644
--- a/Source/CTest/cmCTestUploadCommand.h
+++ b/Source/CTest/cmCTestUploadCommand.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestUploadCommand_h
-#define cmCTestUploadCommand_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -48,5 +47,3 @@ protected:
 
   std::vector<std::string> Files;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestUploadHandler.h b/Source/CTest/cmCTestUploadHandler.h
index dde14df166..55d21c1f08 100644
--- a/Source/CTest/cmCTestUploadHandler.h
+++ b/Source/CTest/cmCTestUploadHandler.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestUploadHandler_h
-#define cmCTestUploadHandler_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -36,5 +35,3 @@ public:
 private:
   std::set<std::string> Files;
 };
-
-#endif
diff --git a/Source/CTest/cmCTestVC.h b/Source/CTest/cmCTestVC.h
index 3037e01c94..9bd7229b3d 100644
--- a/Source/CTest/cmCTestVC.h
+++ b/Source/CTest/cmCTestVC.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCTestVC_h
-#define cmCTestVC_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -150,5 +149,3 @@ protected:
   // Count paths reported with each PathStatus value.
   int PathCount[3];
 };
-
-#endif
diff --git a/Source/CTest/cmParseBlanketJSCoverage.h b/Source/CTest/cmParseBlanketJSCoverage.h
index cd1b225e5d..e107454d16 100644
--- a/Source/CTest/cmParseBlanketJSCoverage.h
+++ b/Source/CTest/cmParseBlanketJSCoverage.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmParseBlanketJSCoverage_h
-#define cmParseBlanketJSCoverage_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -39,4 +38,3 @@ protected:
   cmCTestCoverageHandlerContainer& Coverage;
   cmCTest* CTest;
 };
-#endif
diff --git a/Source/CTest/cmParseCacheCoverage.h b/Source/CTest/cmParseCacheCoverage.h
index a8200b7873..523f83b554 100644
--- a/Source/CTest/cmParseCacheCoverage.h
+++ b/Source/CTest/cmParseCacheCoverage.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmParseCacheCoverage_h
-#define cmParseCacheCoverage_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -31,5 +30,3 @@ protected:
   // Read a single mcov file
   bool ReadCMCovFile(const char* f);
 };
-
-#endif
diff --git a/Source/CTest/cmParseCoberturaCoverage.h b/Source/CTest/cmParseCoberturaCoverage.h
index cb6d0976ba..0340433014 100644
--- a/Source/CTest/cmParseCoberturaCoverage.h
+++ b/Source/CTest/cmParseCoberturaCoverage.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmParseCoberturaCoverage_h
-#define cmParseCoberturaCoverage_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -41,5 +40,3 @@ private:
   cmCTest* CTest;
   std::string CurFileName;
 };
-
-#endif
diff --git a/Source/CTest/cmParseDelphiCoverage.h b/Source/CTest/cmParseDelphiCoverage.h
index 1b374050a5..2a014a198c 100644
--- a/Source/CTest/cmParseDelphiCoverage.h
+++ b/Source/CTest/cmParseDelphiCoverage.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmParseDelphiCoverage_h
-#define cmParseDelphiCoverage_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -35,4 +34,3 @@ protected:
   cmCTestCoverageHandlerContainer& Coverage;
   cmCTest* CTest;
 };
-#endif
diff --git a/Source/CTest/cmParseGTMCoverage.h b/Source/CTest/cmParseGTMCoverage.h
index 41cc7f5754..c35bf6e982 100644
--- a/Source/CTest/cmParseGTMCoverage.h
+++ b/Source/CTest/cmParseGTMCoverage.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmParseGTMCoverage_h
-#define cmParseGTMCoverage_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -37,5 +36,3 @@ protected:
   bool ParseMCOVLine(std::string const& line, std::string& routine,
                      std::string& function, int& linenumber, int& count);
 };
-
-#endif
diff --git a/Source/CTest/cmParseJacocoCoverage.h b/Source/CTest/cmParseJacocoCoverage.h
index f2aec6db92..3442dd03a9 100644
--- a/Source/CTest/cmParseJacocoCoverage.h
+++ b/Source/CTest/cmParseJacocoCoverage.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmParseJacocoCoverage_h
-#define cmParseJacocoCoverage_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -49,5 +48,3 @@ private:
   cmCTestCoverageHandlerContainer& Coverage;
   cmCTest* CTest;
 };
-
-#endif
diff --git a/Source/CTest/cmParseMumpsCoverage.h b/Source/CTest/cmParseMumpsCoverage.h
index 8c0870254c..00a8431edb 100644
--- a/Source/CTest/cmParseMumpsCoverage.h
+++ b/Source/CTest/cmParseMumpsCoverage.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmParseMumpsCoverage_h
-#define cmParseMumpsCoverage_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -43,5 +42,3 @@ protected:
   cmCTestCoverageHandlerContainer& Coverage;
   cmCTest* CTest;
 };
-
-#endif
diff --git a/Source/CTest/cmParsePHPCoverage.h b/Source/CTest/cmParsePHPCoverage.h
index ff0e6366da..763a6bba15 100644
--- a/Source/CTest/cmParsePHPCoverage.h
+++ b/Source/CTest/cmParsePHPCoverage.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmParsePHPCoverage_h
-#define cmParsePHPCoverage_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -35,5 +34,3 @@ private:
   cmCTestCoverageHandlerContainer& Coverage;
   cmCTest* CTest;
 };
-
-#endif
diff --git a/Source/CTest/cmProcess.h b/Source/CTest/cmProcess.h
index 1e6578cf93..9eec9526f5 100644
--- a/Source/CTest/cmProcess.h
+++ b/Source/CTest/cmProcess.h
@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmProcess_h
-#define cmProcess_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -132,5 +131,3 @@ private:
   int Id;
   int64_t ExitValue;
 };
-
-#endif