diff --git a/src/Airports/dynamicloader.cxx b/src/Airports/dynamicloader.cxx
index 53027f63d..986b1dd39 100644
--- a/src/Airports/dynamicloader.cxx
+++ b/src/Airports/dynamicloader.cxx
@@ -13,6 +13,8 @@
 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 //
 
+#include <cstdlib>
+
 #include "dynamicloader.hxx"
 
 FGAirportDynamicsXMLLoader::FGAirportDynamicsXMLLoader(FGAirportDynamics* dyn):
@@ -50,7 +52,7 @@ void  FGAirportDynamicsXMLLoader::startElement (const char * name, const XMLAttr
 	  //cout << "  " << atts.getName(i) << '=' << atts.getValue(i) << endl; 
 	  attname = atts.getName(i);
 	  if (attname == string("index"))
-	    park.setIndex(atoi(atts.getValue(i)));
+	    park.setIndex(std::atoi(atts.getValue(i)));
 	  else if (attname == string("type"))
 	    park.setType(atts.getValue(i));
 	 else if (attname == string("name"))
@@ -62,13 +64,13 @@ void  FGAirportDynamicsXMLLoader::startElement (const char * name, const XMLAttr
 	  else if (attname == string("lon"))
 	    park.setLongitude(atts.getValue(i)); 
 	  else if (attname == string("heading"))
-	    park.setHeading(atof(atts.getValue(i)));
+	    park.setHeading(std::atof(atts.getValue(i)));
 	  else if (attname == string("radius")) {
 	    string radius = atts.getValue(i);
 	    if (radius.find("M") != string::npos)
 	      radius = radius.substr(0, radius.find("M",0));
 	    //cerr << "Radius " << radius <<endl;
-	    park.setRadius(atof(radius.c_str()));
+	    park.setRadius(std::atof(radius.c_str()));
 	  }
 	   else if (attname == string("airlineCodes"))
 	     park.setCodes(atts.getValue(i));
@@ -82,13 +84,13 @@ void  FGAirportDynamicsXMLLoader::startElement (const char * name, const XMLAttr
 	{
 	  attname = atts.getName(i);
 	  if (attname == string("index"))
-	    taxiNode.setIndex(atoi(atts.getValue(i)));
+	    taxiNode.setIndex(std::atoi(atts.getValue(i)));
 	  if (attname == string("lat"))
 	    taxiNode.setLatitude(atts.getValue(i));
 	  if (attname == string("lon"))
 	    taxiNode.setLongitude(atts.getValue(i));
 	  if (attname == string("isOnRunway"))
-            taxiNode.setOnRunway((bool) atoi(atts.getValue(i)));
+            taxiNode.setOnRunway((bool) std::atoi(atts.getValue(i)));
 	  if (attname == string("holdPointType")) {
             attval = atts.getValue(i);
             if (attval==string("none")) {
@@ -113,11 +115,11 @@ void  FGAirportDynamicsXMLLoader::startElement (const char * name, const XMLAttr
 	{
 	  attname = atts.getName(i);
 	  if (attname == string("begin"))
-	    taxiSegment.setStartNodeRef(atoi(atts.getValue(i)));
+	    taxiSegment.setStartNodeRef(std::atoi(atts.getValue(i)));
 	  if (attname == string("end"))
-	    taxiSegment.setEndNodeRef(atoi(atts.getValue(i)));
+	    taxiSegment.setEndNodeRef(std::atoi(atts.getValue(i)));
           if (attname == string("isPushBackRoute"))
-	    taxiSegment.setPushBackType((bool) atoi(atts.getValue(i)));
+	    taxiSegment.setPushBackType((bool) std::atoi(atts.getValue(i)));
 	}
       _dynamics->getGroundNetwork()->addSegment(taxiSegment);
     }
diff --git a/src/Airports/runwayprefloader.cxx b/src/Airports/runwayprefloader.cxx
index 3819a39a8..bfdcf8dd6 100644
--- a/src/Airports/runwayprefloader.cxx
+++ b/src/Airports/runwayprefloader.cxx
@@ -13,10 +13,15 @@
 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 //
 
+#include <cstring>
+#include <cstdlib>
+
 #include <simgear/debug/logstream.hxx>
 
 #include "runwayprefloader.hxx"
 
+using namespace std;
+
 FGRunwayPreferenceXMLLoader::FGRunwayPreferenceXMLLoader(FGRunwayPreference* p):XMLVisitor(), _pref(p) {}
 
 void  FGRunwayPreferenceXMLLoader::startXML () {
diff --git a/src/Airports/runways.cxx b/src/Airports/runways.cxx
index b5770fc82..c1b224522 100644
--- a/src/Airports/runways.cxx
+++ b/src/Airports/runways.cxx
@@ -25,8 +25,9 @@
 #  include <config.h>
 #endif
 
-#include <math.h>               // fabs()
-#include <stdio.h>              // sprintf()
+#include <cmath>               // fabs()
+#include <cstdio>              // sprintf()
+#include <cstdlib>             // atoi()
 
 #include <simgear/compiler.h>
 #include <simgear/debug/logstream.hxx>
diff --git a/src/FDM/JSBSim/input_output/FGfdmSocket.cpp b/src/FDM/JSBSim/input_output/FGfdmSocket.cpp
index 37f29336e..c1a582699 100644
--- a/src/FDM/JSBSim/input_output/FGfdmSocket.cpp
+++ b/src/FDM/JSBSim/input_output/FGfdmSocket.cpp
@@ -37,6 +37,8 @@ HISTORY
 INCLUDES
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
+#include <cstring>
+
 #include "FGfdmSocket.h"
 
 namespace JSBSim {
@@ -79,7 +81,7 @@ FGfdmSocket::FGfdmSocket(string address, int port)
       memset(&scktName, 0, sizeof(struct sockaddr_in));
       scktName.sin_family = AF_INET;
       scktName.sin_port = htons(port);
-      memcpy(&scktName.sin_addr, host->h_addr_list[0], host->h_length);
+      std::memcpy(&scktName.sin_addr, host->h_addr_list[0], host->h_length);
       int len = sizeof(struct sockaddr_in);
       if (connect(sckt, (struct sockaddr*)&scktName, len) == 0) {   // successful
         cout << "Successfully connected to socket for output ..." << endl;
@@ -113,7 +115,7 @@ FGfdmSocket::FGfdmSocket(int port)
   sckt = socket(AF_INET, SOCK_STREAM, 0);
 
   if (sckt >= 0) {  // successful
-    memset(&scktName, 0, sizeof(struct sockaddr_in));
+    std::memset(&scktName, 0, sizeof(struct sockaddr_in));
     scktName.sin_family = AF_INET;
     scktName.sin_port = htons(port);
     int len = sizeof(struct sockaddr_in);
diff --git a/src/FDM/YASim/Airplane.cpp b/src/FDM/YASim/Airplane.cpp
index c6b5ae925..1b3fbd4ba 100644
--- a/src/FDM/YASim/Airplane.cpp
+++ b/src/FDM/YASim/Airplane.cpp
@@ -417,7 +417,7 @@ float Airplane::getTailIncidence()
     return _tailIncidence;
 }
 
-char* Airplane::getFailureMsg()
+const char* Airplane::getFailureMsg()
 {
     return _failureMsg;
 }
diff --git a/src/FDM/YASim/Airplane.hpp b/src/FDM/YASim/Airplane.hpp
index e0e53f4e5..913eb49ed 100644
--- a/src/FDM/YASim/Airplane.hpp
+++ b/src/FDM/YASim/Airplane.hpp
@@ -90,7 +90,7 @@ public:
     float getCruiseAoA();
     float getTailIncidence();
     float getApproachElevator() { return _approachElevator.val; }
-    char* getFailureMsg();
+    const char* getFailureMsg();
 
     static void setupState(float aoa, float speed, float gla, State* s); // utility
 
@@ -172,7 +172,7 @@ private:
     float _cruiseAoA;
     float _tailIncidence;
     Control _approachElevator;
-    char* _failureMsg;
+    const char* _failureMsg;
 };
 
 }; // namespace yasim
diff --git a/src/FDM/YASim/FGFDM.cpp b/src/FDM/YASim/FGFDM.cpp
index 5d68308f1..921fdcf60 100644
--- a/src/FDM/YASim/FGFDM.cpp
+++ b/src/FDM/YASim/FGFDM.cpp
@@ -1013,7 +1013,7 @@ char* FGFDM::dup(const char* s)
     return s2;
 }
 
-int FGFDM::attri(XMLAttributes* atts, char* attr)
+int FGFDM::attri(XMLAttributes* atts, const char* attr)
 {
     if(!atts->hasAttribute(attr)) {
         SG_LOG(SG_FLIGHT,SG_ALERT,"Missing '" << attr <<
@@ -1023,14 +1023,14 @@ int FGFDM::attri(XMLAttributes* atts, char* attr)
     return attri(atts, attr, 0);
 }
 
-int FGFDM::attri(XMLAttributes* atts, char* attr, int def)
+int FGFDM::attri(XMLAttributes* atts, const char* attr, int def)
 {
     const char* val = atts->getValue(attr);
     if(val == 0) return def;
     else         return atol(val);
 }
 
-float FGFDM::attrf(XMLAttributes* atts, char* attr)
+float FGFDM::attrf(XMLAttributes* atts, const char* attr)
 {
     if(!atts->hasAttribute(attr)) {
         SG_LOG(SG_FLIGHT,SG_ALERT,"Missing '" << attr <<
@@ -1040,14 +1040,14 @@ float FGFDM::attrf(XMLAttributes* atts, char* attr)
     return attrf(atts, attr, 0);
 }
 
-float FGFDM::attrf(XMLAttributes* atts, char* attr, float def)
+float FGFDM::attrf(XMLAttributes* atts, const char* attr, float def)
 {
     const char* val = atts->getValue(attr);
     if(val == 0) return def;
     else         return (float)atof(val);    
 }
 
-double FGFDM::attrd(XMLAttributes* atts, char* attr)
+double FGFDM::attrd(XMLAttributes* atts, const char* attr)
 {
     if(!atts->hasAttribute(attr)) {
         SG_LOG(SG_FLIGHT,SG_ALERT,"Missing '" << attr <<
@@ -1057,7 +1057,7 @@ double FGFDM::attrd(XMLAttributes* atts, char* attr)
     return attrd(atts, attr, 0);
 }
 
-double FGFDM::attrd(XMLAttributes* atts, char* attr, double def)
+double FGFDM::attrd(XMLAttributes* atts, const char* attr, double def)
 {
     const char* val = atts->getValue(attr);
     if(val == 0) return def;
@@ -1075,7 +1075,7 @@ double FGFDM::attrd(XMLAttributes* atts, char* attr, double def)
 // Unfortunately, this usage creeped into existing configuration files
 // while I wasn't active, and it's going to be hard to remove.  Issue
 // a warning to nag people into changing their ways for now...
-bool FGFDM::attrb(XMLAttributes* atts, char* attr)
+bool FGFDM::attrb(XMLAttributes* atts, const char* attr)
 {
     const char* val = atts->getValue(attr);
     if(val == 0) return false;
diff --git a/src/FDM/YASim/FGFDM.hpp b/src/FDM/YASim/FGFDM.hpp
index 1df2c4872..0d5b43e37 100644
--- a/src/FDM/YASim/FGFDM.hpp
+++ b/src/FDM/YASim/FGFDM.hpp
@@ -49,13 +49,13 @@ private:
     bool eq(const char* a, const char* b);
     bool caseeq(const char* a, const char* b);
     char* dup(const char* s);
-    int attri(XMLAttributes* atts, char* attr);
-    int attri(XMLAttributes* atts, char* attr, int def); 
-    float attrf(XMLAttributes* atts, char* attr);
-    float attrf(XMLAttributes* atts, char* attr, float def); 
-    double attrd(XMLAttributes* atts, char* attr);
-    double attrd(XMLAttributes* atts, char* attr, double def); 
-    bool attrb(XMLAttributes* atts, char* attr);
+    int attri(XMLAttributes* atts, const char* attr);
+    int attri(XMLAttributes* atts, const char* attr, int def); 
+    float attrf(XMLAttributes* atts, const char* attr);
+    float attrf(XMLAttributes* atts, const char* attr, float def); 
+    double attrd(XMLAttributes* atts, const char* attr);
+    double attrd(XMLAttributes* atts, const char* attr, double def); 
+    bool attrb(XMLAttributes* atts, const char* attr);
 
     // The core Airplane object we manage.
     Airplane _airplane;
diff --git a/src/FDM/YASim/yasim-test.cpp b/src/FDM/YASim/yasim-test.cpp
index cff1c1558..2fa642526 100644
--- a/src/FDM/YASim/yasim-test.cpp
+++ b/src/FDM/YASim/yasim-test.cpp
@@ -1,5 +1,8 @@
 #include <stdio.h>
 
+#include <cstring>
+#include <cstdlib>
+
 #include <simgear/props/props.hxx>
 #include <simgear/xml/easyxml.hxx>
 
@@ -93,8 +96,8 @@ int main(int argc, char** argv)
     if(!a->getFailureMsg() && argc > 2 && strcmp(argv[2], "-g") == 0) {
         float alt = 5000, kts = 100;
         for(int i=3; i<argc; i++) {
-            if     (strcmp(argv[i], "-a") == 0) alt = atof(argv[++i]);
-            else if(strcmp(argv[i], "-s") == 0) kts = atof(argv[++i]);
+            if     (std::strcmp(argv[i], "-a") == 0) alt = std::atof(argv[++i]);
+            else if(std::strcmp(argv[i], "-s") == 0) kts = std::atof(argv[++i]);
             else return usage();
         }
         yasim_graph(a, alt, kts);
diff --git a/src/GUI/gui.h b/src/GUI/gui.h
index bc27d9a30..02717d408 100644
--- a/src/GUI/gui.h
+++ b/src/GUI/gui.h
@@ -67,17 +67,17 @@ extern void printScreen(puObject *);
 extern void helpCb(puObject *);
 
 typedef struct {
-        char *name;
+        const char *name;
         void (*fn)(puObject *);
 } __fg_gui_fn_t;
 extern const __fg_gui_fn_t __fg_gui_fn[];
 
 // GLOBAL COMMON DIALOG BOX TEXT STRINGS
-extern char *gui_msg_OK;     // "OK"
-extern char *gui_msg_NO;     // "NO"
-extern char *gui_msg_YES;    // "YES"
-extern char *gui_msg_CANCEL; // "CANCEL"
-extern char *gui_msg_RESET;  // "RESET"
+extern const char *gui_msg_OK;     // "OK"
+extern const char *gui_msg_NO;     // "NO"
+extern const char *gui_msg_YES;    // "YES"
+extern const char *gui_msg_CANCEL; // "CANCEL"
+extern const char *gui_msg_RESET;  // "RESET"
 
 // mouse.cxx
 extern void guiInitMouse(int width, int height);
diff --git a/src/GUI/gui_funcs.cxx b/src/GUI/gui_funcs.cxx
index 6a57dc1d6..acad392ee 100644
--- a/src/GUI/gui_funcs.cxx
+++ b/src/GUI/gui_funcs.cxx
@@ -103,11 +103,11 @@ extern void fgUpdateHUD( GLfloat x_start, GLfloat y_start,
 
 
 // TODO: remove after the last hardcoded dialog has died
-char *gui_msg_OK     = "OK";
-char *gui_msg_NO     = "NO";
-char *gui_msg_YES    = "YES";
-char *gui_msg_CANCEL = "CANCEL";
-char *gui_msg_RESET  = "RESET";
+const char *gui_msg_OK     = "OK";
+const char *gui_msg_NO     = "NO";
+const char *gui_msg_YES    = "YES";
+const char *gui_msg_CANCEL = "CANCEL";
+const char *gui_msg_RESET  = "RESET";
 
 
 const __fg_gui_fn_t __fg_gui_fn[] = {
diff --git a/src/Main/util.cxx b/src/Main/util.cxx
index 6b916e862..b61985ca6 100644
--- a/src/Main/util.cxx
+++ b/src/Main/util.cxx
@@ -22,6 +22,8 @@
 
 #include <math.h>
 
+#include <cstdlib>
+
 #include <vector>
 SG_USING_STD(vector);
 
@@ -112,7 +114,7 @@ fgExit (int status)
 #endif
 
     SG_LOG(SG_GENERAL, SG_INFO, "Exiting FlightGear with status " << status);
-    exit(status);
+    std::exit(status);
 }
 
 
diff --git a/utils/GPSsmooth/UGear_command.cxx b/utils/GPSsmooth/UGear_command.cxx
index 7e64cc887..85485749f 100644
--- a/utils/GPSsmooth/UGear_command.cxx
+++ b/utils/GPSsmooth/UGear_command.cxx
@@ -1,3 +1,5 @@
+#include <cstring>
+
 #include "UGear_command.hxx"
 
 
@@ -18,7 +20,7 @@ static char calc_nmea_cksum(const char *sentence) {
 
     // cout << sentence << endl;
 
-    len = strlen(sentence);
+    len = std::strlen(sentence);
     sum = sentence[0];
     for ( i = 1; i < len; i++ ) {
         // cout << sentence[i];