diff --git a/applications/test/alloc/Test-malloc.C b/applications/test/alloc/Test-malloc.C
index 1614987e3c..4bfc18a20e 100644
--- a/applications/test/alloc/Test-malloc.C
+++ b/applications/test/alloc/Test-malloc.C
@@ -1,6 +1,6 @@
 #include "stream.h"
 #include <unistd.h>
-#include <stdlib.h>
+#include <cstdlib>
 
 main()
 {
diff --git a/applications/test/alloc/Test.C b/applications/test/alloc/Test.C
index 67f77ab05c..a2de8b24df 100644
--- a/applications/test/alloc/Test.C
+++ b/applications/test/alloc/Test.C
@@ -1,4 +1,4 @@
-#include <stdlib.h>
+#include <cstdlib>
 
 class Int
 {
diff --git a/applications/test/maxMem/Test-maxMem.C b/applications/test/maxMem/Test-maxMem.C
index 590c542ee9..3a6c5c5c6e 100644
--- a/applications/test/maxMem/Test-maxMem.C
+++ b/applications/test/maxMem/Test-maxMem.C
@@ -1,5 +1,6 @@
 #include <iostream>
-#include <stdlib.h>
+#include <cstdlib>
+
 using namespace std;
 
 int main(int argc, char *argv[])
diff --git a/applications/utilities/miscellaneous/OSspecific/addr2line/addr2line.C b/applications/utilities/miscellaneous/OSspecific/addr2line/addr2line.C
index 928c17216a..399f81b507 100644
--- a/applications/utilities/miscellaneous/OSspecific/addr2line/addr2line.C
+++ b/applications/utilities/miscellaneous/OSspecific/addr2line/addr2line.C
@@ -121,14 +121,14 @@ void usage()
     std::cout
         << "usage: addr2line [-e filename|--exe=filename]"
            " address [address...]\n" << std::endl;
-    ::exit(1);
+    std::exit(1);
 }
 
 
 void version()
 {
     std::cout<< "OpenFOAM addr2line emulator\n" << std::endl;
-    ::exit(0);
+    std::exit(0);
 }
 
 
diff --git a/src/OpenFOAM/db/dictionary/dictionary.C b/src/OpenFOAM/db/dictionary/dictionary.C
index 37ba5fe667..775d90ea59 100644
--- a/src/OpenFOAM/db/dictionary/dictionary.C
+++ b/src/OpenFOAM/db/dictionary/dictionary.C
@@ -272,7 +272,7 @@ void Foam::dictionary::checkITstream
                 << " at line " << is.lineNumber() << '.' << nl
                 << std::endl;
 
-            ::exit(1);
+            std::exit(1);
         }
     }
     else if (!is.size())
@@ -305,7 +305,7 @@ void Foam::dictionary::checkITstream
                 << " at line " << is.lineNumber() << '.' << nl
                 << std::endl;
 
-            ::exit(1);
+            std::exit(1);
         }
     }
 }
diff --git a/src/OpenFOAM/db/dictionary/entry/entry.C b/src/OpenFOAM/db/dictionary/entry/entry.C
index eccfa396c7..9bd55a3e05 100644
--- a/src/OpenFOAM/db/dictionary/entry/entry.C
+++ b/src/OpenFOAM/db/dictionary/entry/entry.C
@@ -116,7 +116,7 @@ void Foam::entry::checkITstream(const ITstream& is) const
                 << " at line " << is.lineNumber() << '.' << nl
                 << std::endl;
 
-            ::exit(1);
+            std::exit(1);
         }
     }
     else if (!is.size())
@@ -149,7 +149,7 @@ void Foam::entry::checkITstream(const ITstream& is) const
                 << " at line " << is.lineNumber() << '.' << nl
                 << std::endl;
 
-            ::exit(1);
+            std::exit(1);
         }
     }
 }
diff --git a/src/OpenFOAM/db/error/IOerror.C b/src/OpenFOAM/db/error/IOerror.C
index 51b007342b..d3b51b3e71 100644
--- a/src/OpenFOAM/db/error/IOerror.C
+++ b/src/OpenFOAM/db/error/IOerror.C
@@ -153,7 +153,7 @@ void Foam::IOerror::SafeFatalIOError
             << "    in file " << sourceFileName
             << " at line " << sourceFileLineNumber << '.'
             << std::endl;
-        ::exit(1);
+        std::exit(1);
     }
 }
 
@@ -210,7 +210,7 @@ void Foam::IOerror::exit(const int)
         {
             Perr<< endl << *this << endl
                 << "\nFOAM exiting\n" << endl;
-            ::exit(1);
+            std::exit(1);
         }
     }
 }
@@ -229,7 +229,7 @@ void Foam::IOerror::abort()
         Perr<< endl << *this << endl
             << "\nFOAM aborting (FOAM_ABORT set)\n" << endl;
         printStack(Perr);
-        ::abort();
+        std::abort();
     }
 
     if (Pstream::parRun())
@@ -256,7 +256,7 @@ void Foam::IOerror::abort()
             Perr<< endl << *this << endl
                 << "\nFOAM aborting\n" << endl;
             printStack(Perr);
-            ::abort();
+            std::abort();
         }
     }
 }
diff --git a/src/OpenFOAM/db/error/error.C b/src/OpenFOAM/db/error/error.C
index 8140ed6f9c..c143fcf5f1 100644
--- a/src/OpenFOAM/db/error/error.C
+++ b/src/OpenFOAM/db/error/error.C
@@ -244,7 +244,7 @@ void Foam::error::exit(const int errNo)
     {
         Perr<< endl << *this << endl
             << "\nFOAM exiting\n" << endl;
-        ::exit(errNo);
+        std::exit(errNo);
     }
 }
 
@@ -262,7 +262,7 @@ void Foam::error::abort()
         Perr<< endl << *this << endl
             << "\nFOAM aborting (FOAM_ABORT set)\n" << endl;
         printStack(Perr);
-        ::abort();
+        std::abort();
     }
 
     if (throwExceptions_)
@@ -287,7 +287,7 @@ void Foam::error::abort()
         Perr<< endl << *this << endl
             << "\nFOAM aborting\n" << endl;
         printStack(Perr);
-        ::abort();
+        std::abort();
     }
 }
 
diff --git a/src/OpenFOAM/db/functionObjects/functionObjectList/functionObjectList.C b/src/OpenFOAM/db/functionObjects/functionObjectList/functionObjectList.C
index a95b8d1b2b..bdb0128ceb 100644
--- a/src/OpenFOAM/db/functionObjects/functionObjectList/functionObjectList.C
+++ b/src/OpenFOAM/db/functionObjects/functionObjectList/functionObjectList.C
@@ -887,7 +887,7 @@ bool Foam::functionObjectList::read()
                 catch (const Foam::IOerror& ioErr)
                 {
                     Info<< ioErr << nl << endl;
-                    ::exit(1);
+                    std::exit(1);
                 }
                 catch (const Foam::error& err)
                 {
diff --git a/src/OpenFOAM/global/argList/argList.C b/src/OpenFOAM/global/argList/argList.C
index 8a100b33cb..f9daf29dc8 100644
--- a/src/OpenFOAM/global/argList/argList.C
+++ b/src/OpenFOAM/global/argList/argList.C
@@ -906,7 +906,7 @@ void Foam::argList::parse
 
         if (quickExit)
         {
-            ::exit(0);
+            std::exit(0);
         }
     }
 
diff --git a/src/OpenFOAM/global/debug/debug.C b/src/OpenFOAM/global/debug/debug.C
index a22251d9ce..bdbc0ce8c4 100644
--- a/src/OpenFOAM/global/debug/debug.C
+++ b/src/OpenFOAM/global/debug/debug.C
@@ -147,7 +147,7 @@ Foam::dictionary& Foam::debug::switchSet
                 << controlDict().name().c_str()
                 << std::endl << std::endl;
 
-            ::exit(1);
+            std::exit(1);
         }
 
         subDictPtr = &(eptr->dict());
diff --git a/src/OpenFOAM/global/etcFiles/etcFiles.C b/src/OpenFOAM/global/etcFiles/etcFiles.C
index de3c6f83c7..3e04dbe70f 100644
--- a/src/OpenFOAM/global/etcFiles/etcFiles.C
+++ b/src/OpenFOAM/global/etcFiles/etcFiles.C
@@ -82,7 +82,7 @@ static inline void errorMandatoryNotFound
         << locationToString(location) << ")\n    '"
         << name << "'\n"
         << std::endl;
-    ::exit(1);
+    std::exit(1);
 }
 
 
diff --git a/src/OpenFOAM/global/new.C b/src/OpenFOAM/global/new.C
index ac7f38f077..d98ec3d2fd 100644
--- a/src/OpenFOAM/global/new.C
+++ b/src/OpenFOAM/global/new.C
@@ -46,7 +46,7 @@ void newError()
         "by e.g. bad use of pointers or an out of date shared library"
         << std::endl;
 
-    ::abort();
+    std::abort();
 }
 
 void (*old_new_handler)() = std::set_new_handler(newError);
diff --git a/src/Pstream/dummy/UPstream.C b/src/Pstream/dummy/UPstream.C
index 661e5a2cc5..9dbaf0f574 100644
--- a/src/Pstream/dummy/UPstream.C
+++ b/src/Pstream/dummy/UPstream.C
@@ -58,14 +58,14 @@ bool Foam::UPstream::init(int& argc, char**& argv, const bool needsThread)
 void Foam::UPstream::exit(int errnum)
 {
     // No MPI - just exit
-    ::exit(errnum);
+    std::exit(errnum);
 }
 
 
 void Foam::UPstream::abort()
 {
     // No MPI - just abort
-    ::abort();
+    std::abort();
 }
 
 
diff --git a/src/Pstream/mpi/UPstream.C b/src/Pstream/mpi/UPstream.C
index 5a2ec78973..0fec38de2c 100644
--- a/src/Pstream/mpi/UPstream.C
+++ b/src/Pstream/mpi/UPstream.C
@@ -213,7 +213,7 @@ void Foam::UPstream::exit(int errnum)
     if (!flag)
     {
         // Not initialized - just exit
-        ::exit(errnum);
+        std::exit(errnum);
         return;
     }
 
@@ -224,7 +224,7 @@ void Foam::UPstream::exit(int errnum)
         WarningInFunction
             << "MPI was already finalized (perhaps by a connected program)"
             << endl;
-        ::exit(1);
+        std::exit(1);
         return;
     }
 
@@ -271,7 +271,7 @@ void Foam::UPstream::exit(int errnum)
     if (errnum == 0)
     {
         MPI_Finalize();
-        ::exit(errnum);
+        std::exit(errnum);
     }
     else
     {
diff --git a/src/conversion/ccm/common/ccmInternal.C b/src/conversion/ccm/common/ccmInternal.C
index 47dd0c3933..42698b4924 100644
--- a/src/conversion/ccm/common/ccmInternal.C
+++ b/src/conversion/ccm/common/ccmInternal.C
@@ -118,7 +118,7 @@ bool Foam::ccm::ccmGlobalState::assertNoError
             << "\n    libccmio reports -> " << errorMsg(err) << " <-\n"
             << endl;
 
-        ::exit(1);
+        std::exit(1);
     }
 
     return (err == kCCMIONoErr);
diff --git a/src/mesh/snappyHexMesh/snappyHexMeshDriver/snappyLayerDriver.C b/src/mesh/snappyHexMesh/snappyHexMeshDriver/snappyLayerDriver.C
index 6518115a13..c8269b51d8 100644
--- a/src/mesh/snappyHexMesh/snappyHexMeshDriver/snappyLayerDriver.C
+++ b/src/mesh/snappyHexMesh/snappyHexMeshDriver/snappyLayerDriver.C
@@ -3916,7 +3916,7 @@ void Foam::snappyLayerDriver::addLayers
                     else
                     {
                         Perr<< "\nFOAM exiting\n" << endl;
-                        ::exit(0);
+                        std::exit(0);
                     }
                 }
             }