diff --git a/src/audio-sdlmixer.h b/src/audio-sdlmixer.h
index ee33ef2c..5ff4530b 100644
--- a/src/audio-sdlmixer.h
+++ b/src/audio-sdlmixer.h
@@ -40,7 +40,7 @@ class ExceptionSDLmixer : public ExceptionAudio {
   explicit ExceptionSDLmixer(const std::string &description);
   virtual ~ExceptionSDLmixer() {}
 
-  virtual std::string get_platform() const { return "SDL_mixer"; }
+  virtual const std::string get_platform() const { return "SDL_mixer"; }
 };
 
 class AudioSDL : public Audio, public Audio::VolumeController {
diff --git a/src/audio.cc b/src/audio.cc
index b746b741..2a03d0bb 100644
--- a/src/audio.cc
+++ b/src/audio.cc
@@ -33,7 +33,7 @@ ExceptionAudio::ExceptionAudio(const std::string &description) :
 ExceptionAudio::~ExceptionAudio() {
 }
 
-std::string
+const std::string
 ExceptionAudio::get_description() const {
   return "[" + get_system() + ":" + get_platform() + "] " + description.c_str();
 }
diff --git a/src/audio.h b/src/audio.h
index 1f059326..850e94ba 100644
--- a/src/audio.h
+++ b/src/audio.h
@@ -34,9 +34,9 @@ class ExceptionAudio : public ExceptionFreeserf {
   explicit ExceptionAudio(const std::string &description);
   virtual ~ExceptionAudio();
 
-  virtual std::string get_description() const;
-  virtual std::string get_platform() const { return "Abstract"; }
-  virtual std::string get_system() const { return "audio"; }
+  virtual const std::string get_description() const;
+  virtual const std::string get_platform() const { return "Abstract"; }
+  virtual const std::string get_system() const { return "audio"; }
 };
 
 class Audio {
diff --git a/src/debug.cc b/src/debug.cc
index cf74f287..577642f8 100644
--- a/src/debug.cc
+++ b/src/debug.cc
@@ -21,8 +21,8 @@
 
 #include "src/debug.h"
 
-ExceptionFreeserf::ExceptionFreeserf(const std::string &description_) throw()
-  : description(description_) {
+ExceptionFreeserf::ExceptionFreeserf(const std::string &description_) throw() {
+  description = "[" + get_system() + "] " + description_;
 }
 
 ExceptionFreeserf::~ExceptionFreeserf() {
@@ -30,10 +30,10 @@ ExceptionFreeserf::~ExceptionFreeserf() {
 
 const char*
 ExceptionFreeserf::what() const throw() {
-  return get_description().c_str();
+  return description.c_str();
 }
 
-std::string
+const std::string
 ExceptionFreeserf::get_description() const {
-  return "[" + get_system() + "] " + description;
+  return description;
 }
diff --git a/src/debug.h b/src/debug.h
index 23c63b43..00d16bfd 100644
--- a/src/debug.h
+++ b/src/debug.h
@@ -35,8 +35,8 @@ class ExceptionFreeserf : public std::exception {
   virtual ~ExceptionFreeserf();
 
   virtual const char* what() const throw();
-  virtual std::string get_description() const;
-  virtual std::string get_system() const { return "Unspecified"; }
+  virtual const std::string get_description() const;
+  virtual const std::string get_system() const { return "Unspecified"; }
 };
 
 #ifndef NDEBUG
diff --git a/src/gfx.h b/src/gfx.h
index 267267ff..188dd1bd 100644
--- a/src/gfx.h
+++ b/src/gfx.h
@@ -35,7 +35,7 @@ class ExceptionGFX : public ExceptionFreeserf {
   explicit ExceptionGFX(const std::string &description);
   virtual ~ExceptionGFX();
 
-  virtual std::string get_system() const { return "graphics"; }
+  virtual const std::string get_system() const { return "graphics"; }
 };
 
 class Color {
diff --git a/src/video-sdl.h b/src/video-sdl.h
index 98cb71e2..f3b85673 100644
--- a/src/video-sdl.h
+++ b/src/video-sdl.h
@@ -53,7 +53,7 @@ class ExceptionSDL : public ExceptionVideo {
   explicit ExceptionSDL(const std::string &description) throw();
   virtual ~ExceptionSDL() {}
 
-  virtual std::string get_platform() const { return "SDL"; }
+  virtual const std::string get_platform() const { return "SDL"; }
 };
 
 class VideoSDL : public Video {
diff --git a/src/video.cc b/src/video.cc
index f654af6d..cf270adc 100644
--- a/src/video.cc
+++ b/src/video.cc
@@ -30,7 +30,7 @@ ExceptionVideo::ExceptionVideo(const std::string &description) :
 ExceptionVideo::~ExceptionVideo() {
 }
 
-std::string
+const std::string
 ExceptionVideo::get_description() const {
   return "[" + get_system() + ":" + get_platform() + "] " + description.c_str();
 }
diff --git a/src/video.h b/src/video.h
index ba2396f8..98b3e378 100644
--- a/src/video.h
+++ b/src/video.h
@@ -32,9 +32,9 @@ class ExceptionVideo : public ExceptionFreeserf {
   explicit ExceptionVideo(const std::string &description);
   virtual ~ExceptionVideo();
 
-  virtual std::string get_description() const;
-  virtual std::string get_platform() const { return "Abstract"; }
-  virtual std::string get_system() const { return "video"; }
+  virtual const std::string get_description() const;
+  virtual const std::string get_platform() const { return "Abstract"; }
+  virtual const std::string get_system() const { return "video"; }
 };
 
 class Video {