diff --git a/Action.h b/Action.h
index 625bff6c..ed13612c 100644
--- a/Action.h
+++ b/Action.h
@@ -37,19 +37,19 @@ typedef struct State_ {
 } State;
 
 
-extern Object* Action_pickFromVector(State* st, Panel* list, int x, bool followProcess);
+Object* Action_pickFromVector(State* st, Panel* list, int x, bool followProcess);
 
 // ----------------------------------------
 
-extern bool Action_setUserOnly(const char* userName, uid_t* userId);
+bool Action_setUserOnly(const char* userName, uid_t* userId);
 
-extern Htop_Reaction Action_setSortKey(Settings* settings, ProcessField sortKey);
+Htop_Reaction Action_setSortKey(Settings* settings, ProcessField sortKey);
 
 // ----------------------------------------
 
-extern Htop_Reaction Action_follow(State* st);
+Htop_Reaction Action_follow(State* st);
 
 
-extern void Action_setBindings(Htop_Action* keys);
+void Action_setBindings(Htop_Action* keys);
 
 #endif
diff --git a/Affinity.h b/Affinity.h
index 322ca549..8ee158d6 100644
--- a/Affinity.h
+++ b/Affinity.h
@@ -28,23 +28,23 @@ typedef struct Affinity_ {
 } Affinity;
 
 
-extern Affinity* Affinity_new(ProcessList* pl);
+Affinity* Affinity_new(ProcessList* pl);
 
-extern void Affinity_delete(Affinity* this);
+void Affinity_delete(Affinity* this);
 
-extern void Affinity_add(Affinity* this, int id);
+void Affinity_add(Affinity* this, int id);
 
 #ifdef HAVE_LIBHWLOC
 
-extern Affinity* Affinity_get(Process* proc, ProcessList* pl);
+Affinity* Affinity_get(Process* proc, ProcessList* pl);
 
-extern bool Affinity_set(Process* proc, Arg arg);
+bool Affinity_set(Process* proc, Arg arg);
 
 #elif HAVE_LINUX_AFFINITY
 
-extern Affinity* Affinity_get(Process* proc, ProcessList* pl);
+Affinity* Affinity_get(Process* proc, ProcessList* pl);
 
-extern bool Affinity_set(Process* proc, Arg arg);
+bool Affinity_set(Process* proc, Arg arg);
 
 #endif
 
diff --git a/AffinityPanel.h b/AffinityPanel.h
index 64ee32ad..f6ed350d 100644
--- a/AffinityPanel.h
+++ b/AffinityPanel.h
@@ -31,8 +31,8 @@ in the source distribution for its full text.
 
 extern PanelClass AffinityPanel_class;
 
-extern Panel* AffinityPanel_new(ProcessList* pl, Affinity* affinity, int* width);
+Panel* AffinityPanel_new(ProcessList* pl, Affinity* affinity, int* width);
 
-extern Affinity* AffinityPanel_getAffinity(Panel* super, ProcessList* pl);
+Affinity* AffinityPanel_getAffinity(Panel* super, ProcessList* pl);
 
 #endif
diff --git a/AvailableColumnsPanel.h b/AvailableColumnsPanel.h
index fc3cb219..ad70fbbb 100644
--- a/AvailableColumnsPanel.h
+++ b/AvailableColumnsPanel.h
@@ -17,6 +17,6 @@ typedef struct AvailableColumnsPanel_ {
 
 extern PanelClass AvailableColumnsPanel_class;
 
-extern AvailableColumnsPanel* AvailableColumnsPanel_new(Panel* columns);
+AvailableColumnsPanel* AvailableColumnsPanel_new(Panel* columns);
 
 #endif
diff --git a/AvailableMetersPanel.h b/AvailableMetersPanel.h
index b2de6719..93db0dac 100644
--- a/AvailableMetersPanel.h
+++ b/AvailableMetersPanel.h
@@ -25,6 +25,6 @@ typedef struct AvailableMetersPanel_ {
 
 extern PanelClass AvailableMetersPanel_class;
 
-extern AvailableMetersPanel* AvailableMetersPanel_new(Settings* settings, Header* header, Panel* leftMeters, Panel* rightMeters, ScreenManager* scr, ProcessList* pl);
+AvailableMetersPanel* AvailableMetersPanel_new(Settings* settings, Header* header, Panel* leftMeters, Panel* rightMeters, ScreenManager* scr, ProcessList* pl);
 
 #endif
diff --git a/CRT.h b/CRT.h
index 351f6397..398fed31 100644
--- a/CRT.h
+++ b/CRT.h
@@ -127,9 +127,9 @@ typedef enum ColorElements_ {
    LAST_COLORELEMENT
 } ColorElements;
 
-extern void CRT_fatalError(const char* note) __attribute__ ((noreturn));
+void CRT_fatalError(const char* note) __attribute__ ((noreturn));
 
-extern void CRT_handleSIGSEGV(int sgn);
+void CRT_handleSIGSEGV(int sgn);
 
 #define KEY_ALT(x) (KEY_F(64 - 26) + (x - 'A'))
 
@@ -170,9 +170,9 @@ extern void *backtraceArray[128];
 
 #define DIE(msg) do { CRT_done(); fprintf(stderr, msg); exit(1); } while(0)
 
-extern void CRT_dropPrivileges();
+void CRT_dropPrivileges();
 
-extern void CRT_restorePrivileges();
+void CRT_restorePrivileges();
 
 #else
 
@@ -187,18 +187,18 @@ extern void CRT_restorePrivileges();
 
 // TODO: pass an instance of Settings instead.
 
-extern void CRT_init(int delay, int colorScheme, bool allowUnicode);
+void CRT_init(int delay, int colorScheme, bool allowUnicode);
 
-extern void CRT_done();
+void CRT_done();
 
-extern void CRT_fatalError(const char* note);
+void CRT_fatalError(const char* note);
 
-extern int CRT_readKey();
+int CRT_readKey();
 
-extern void CRT_disableDelay();
+void CRT_disableDelay();
 
-extern void CRT_enableDelay();
+void CRT_enableDelay();
 
-extern void CRT_setColors(int colorScheme);
+void CRT_setColors(int colorScheme);
 
 #endif
diff --git a/CategoriesPanel.h b/CategoriesPanel.h
index dd637e7a..e6c7026d 100644
--- a/CategoriesPanel.h
+++ b/CategoriesPanel.h
@@ -22,10 +22,10 @@ typedef struct CategoriesPanel_ {
 } CategoriesPanel;
 
 
-extern void CategoriesPanel_makeMetersPage(CategoriesPanel* this);
+void CategoriesPanel_makeMetersPage(CategoriesPanel* this);
 
 extern PanelClass CategoriesPanel_class;
 
-extern CategoriesPanel* CategoriesPanel_new(ScreenManager* scr, Settings* settings, Header* header, ProcessList* pl);
+CategoriesPanel* CategoriesPanel_new(ScreenManager* scr, Settings* settings, Header* header, ProcessList* pl);
 
 #endif
diff --git a/CheckItem.h b/CheckItem.h
index f59cc78e..654c21f4 100644
--- a/CheckItem.h
+++ b/CheckItem.h
@@ -19,12 +19,12 @@ typedef struct CheckItem_ {
 
 extern ObjectClass CheckItem_class;
 
-extern CheckItem* CheckItem_newByRef(char* text, bool* ref);
+CheckItem* CheckItem_newByRef(char* text, bool* ref);
 
-extern CheckItem* CheckItem_newByVal(char* text, bool value);
+CheckItem* CheckItem_newByVal(char* text, bool value);
 
-extern void CheckItem_set(CheckItem* this, bool value);
+void CheckItem_set(CheckItem* this, bool value);
 
-extern bool CheckItem_get(CheckItem* this);
+bool CheckItem_get(CheckItem* this);
 
 #endif
diff --git a/ColorsPanel.h b/ColorsPanel.h
index 337a7f43..96a82a42 100644
--- a/ColorsPanel.h
+++ b/ColorsPanel.h
@@ -27,6 +27,6 @@ typedef struct ColorsPanel_ {
 
 extern PanelClass ColorsPanel_class;
 
-extern ColorsPanel* ColorsPanel_new(Settings* settings, ScreenManager* scr);
+ColorsPanel* ColorsPanel_new(Settings* settings, ScreenManager* scr);
 
 #endif
diff --git a/ColumnsPanel.h b/ColumnsPanel.h
index e3d4bcb9..89f500ab 100644
--- a/ColumnsPanel.h
+++ b/ColumnsPanel.h
@@ -20,10 +20,10 @@ typedef struct ColumnsPanel_ {
 
 extern PanelClass ColumnsPanel_class;
 
-extern ColumnsPanel* ColumnsPanel_new(Settings* settings);
+ColumnsPanel* ColumnsPanel_new(Settings* settings);
 
-extern int ColumnsPanel_fieldNameToIndex(const char* name);
+int ColumnsPanel_fieldNameToIndex(const char* name);
 
-extern void ColumnsPanel_update(Panel* super);
+void ColumnsPanel_update(Panel* super);
 
 #endif
diff --git a/DisplayOptionsPanel.h b/DisplayOptionsPanel.h
index b3830541..69b8a3d5 100644
--- a/DisplayOptionsPanel.h
+++ b/DisplayOptionsPanel.h
@@ -21,6 +21,6 @@ typedef struct DisplayOptionsPanel_ {
 
 extern PanelClass DisplayOptionsPanel_class;
 
-extern DisplayOptionsPanel* DisplayOptionsPanel_new(Settings* settings, ScreenManager* scr);
+DisplayOptionsPanel* DisplayOptionsPanel_new(Settings* settings, ScreenManager* scr);
 
 #endif
diff --git a/EnvScreen.h b/EnvScreen.h
index 15f7acaa..54dfa41a 100644
--- a/EnvScreen.h
+++ b/EnvScreen.h
@@ -9,12 +9,12 @@ typedef struct EnvScreen_ {
 
 extern InfoScreenClass EnvScreen_class;
 
-extern EnvScreen* EnvScreen_new(Process* process);
+EnvScreen* EnvScreen_new(Process* process);
 
-extern void EnvScreen_delete(Object* this);
+void EnvScreen_delete(Object* this);
 
-extern void EnvScreen_draw(InfoScreen* this);
+void EnvScreen_draw(InfoScreen* this);
 
-extern void EnvScreen_scan(InfoScreen* this);
+void EnvScreen_scan(InfoScreen* this);
 
 #endif
diff --git a/FunctionBar.h b/FunctionBar.h
index 09652e8b..8971d1a5 100644
--- a/FunctionBar.h
+++ b/FunctionBar.h
@@ -20,18 +20,18 @@ typedef struct FunctionBar_ {
 
 
 
-extern FunctionBar* FunctionBar_newEnterEsc(const char* enter, const char* esc);
+FunctionBar* FunctionBar_newEnterEsc(const char* enter, const char* esc);
 
-extern FunctionBar* FunctionBar_new(const char* const* functions, const char* const* keys, const int* events);
+FunctionBar* FunctionBar_new(const char* const* functions, const char* const* keys, const int* events);
 
-extern void FunctionBar_delete(FunctionBar* this);
+void FunctionBar_delete(FunctionBar* this);
 
-extern void FunctionBar_setLabel(FunctionBar* this, int event, const char* text);
+void FunctionBar_setLabel(FunctionBar* this, int event, const char* text);
 
-extern void FunctionBar_draw(const FunctionBar* this, char* buffer);
+void FunctionBar_draw(const FunctionBar* this, char* buffer);
 
-extern void FunctionBar_drawAttr(const FunctionBar* this, char* buffer, int attr);
+void FunctionBar_drawAttr(const FunctionBar* this, char* buffer, int attr);
 
-extern int FunctionBar_synthesizeEvent(const FunctionBar* this, int pos);
+int FunctionBar_synthesizeEvent(const FunctionBar* this, int pos);
 
 #endif
diff --git a/Hashtable.h b/Hashtable.h
index 651f1648..144f01cf 100644
--- a/Hashtable.h
+++ b/Hashtable.h
@@ -28,20 +28,20 @@ struct Hashtable_ {
 
 #ifdef DEBUG
 
-extern int Hashtable_count(Hashtable* this);
+int Hashtable_count(Hashtable* this);
 
 #endif
 
-extern Hashtable* Hashtable_new(int size, bool owner);
+Hashtable* Hashtable_new(int size, bool owner);
 
-extern void Hashtable_delete(Hashtable* this);
+void Hashtable_delete(Hashtable* this);
 
-extern void Hashtable_put(Hashtable* this, unsigned int key, void* value);
+void Hashtable_put(Hashtable* this, unsigned int key, void* value);
 
-extern void* Hashtable_remove(Hashtable* this, unsigned int key);
+void* Hashtable_remove(Hashtable* this, unsigned int key);
 
-extern void* Hashtable_get(Hashtable* this, unsigned int key);
+void* Hashtable_get(Hashtable* this, unsigned int key);
 
-extern void Hashtable_foreach(Hashtable* this, Hashtable_PairFunction f, void* userData);
+void Hashtable_foreach(Hashtable* this, Hashtable_PairFunction f, void* userData);
 
 #endif
diff --git a/Header.h b/Header.h
index 844d04c9..73f264dc 100644
--- a/Header.h
+++ b/Header.h
@@ -29,30 +29,30 @@ typedef struct Header_ {
 #define Header_forEachColumn(this_, i_) for (int (i_)=0; (i_) < (this_)->nrColumns; ++(i_))
 #endif
 
-extern Header* Header_new(struct ProcessList_* pl, Settings* settings, int nrColumns);
+Header* Header_new(struct ProcessList_* pl, Settings* settings, int nrColumns);
 
-extern void Header_delete(Header* this);
+void Header_delete(Header* this);
 
-extern void Header_populateFromSettings(Header* this);
+void Header_populateFromSettings(Header* this);
 
-extern void Header_writeBackToSettings(const Header* this);
+void Header_writeBackToSettings(const Header* this);
 
-extern MeterModeId Header_addMeterByName(Header* this, char* name, int column);
+MeterModeId Header_addMeterByName(Header* this, char* name, int column);
 
-extern void Header_setMode(Header* this, int i, MeterModeId mode, int column);
+void Header_setMode(Header* this, int i, MeterModeId mode, int column);
 
-extern Meter* Header_addMeterByClass(Header* this, MeterClass* type, int param, int column);
+Meter* Header_addMeterByClass(Header* this, MeterClass* type, int param, int column);
 
-extern int Header_size(Header* this, int column);
+int Header_size(Header* this, int column);
 
-extern char* Header_readMeterName(Header* this, int i, int column);
+char* Header_readMeterName(Header* this, int i, int column);
 
-extern MeterModeId Header_readMeterMode(Header* this, int i, int column);
+MeterModeId Header_readMeterMode(Header* this, int i, int column);
 
-extern void Header_reinit(Header* this);
+void Header_reinit(Header* this);
 
-extern void Header_draw(const Header* this);
+void Header_draw(const Header* this);
 
-extern int Header_calculateHeight(Header* this);
+int Header_calculateHeight(Header* this);
 
 #endif
diff --git a/IncSet.h b/IncSet.h
index b75b234b..75949b0a 100644
--- a/IncSet.h
+++ b/IncSet.h
@@ -39,24 +39,24 @@ typedef struct IncSet_ {
 typedef const char* (*IncMode_GetPanelValue)(Panel*, int);
 
 
-extern void IncSet_reset(IncSet* this, IncType type);
+void IncSet_reset(IncSet* this, IncType type);
 
-extern IncSet* IncSet_new(FunctionBar* bar);
+IncSet* IncSet_new(FunctionBar* bar);
 
-extern void IncSet_delete(IncSet* this);
+void IncSet_delete(IncSet* this);
 
-extern bool IncSet_next(IncSet* this, IncType type, Panel* panel, IncMode_GetPanelValue getPanelValue);
+bool IncSet_next(IncSet* this, IncType type, Panel* panel, IncMode_GetPanelValue getPanelValue);
 
-extern bool IncSet_prev(IncSet* this, IncType type, Panel* panel, IncMode_GetPanelValue getPanelValue);
+bool IncSet_prev(IncSet* this, IncType type, Panel* panel, IncMode_GetPanelValue getPanelValue);
 
-extern bool IncSet_handleKey(IncSet* this, int ch, Panel* panel, IncMode_GetPanelValue getPanelValue, Vector* lines);
+bool IncSet_handleKey(IncSet* this, int ch, Panel* panel, IncMode_GetPanelValue getPanelValue, Vector* lines);
 
-extern const char* IncSet_getListItemValue(Panel* panel, int i);
+const char* IncSet_getListItemValue(Panel* panel, int i);
 
-extern void IncSet_activate(IncSet* this, IncType type, Panel* panel);
+void IncSet_activate(IncSet* this, IncType type, Panel* panel);
 
-extern void IncSet_drawBar(IncSet* this);
+void IncSet_drawBar(IncSet* this);
 
-extern int IncSet_synthesizeEvent(IncSet* this, int x);
+int IncSet_synthesizeEvent(IncSet* this, int x);
 
 #endif
diff --git a/InfoScreen.h b/InfoScreen.h
index b59527f3..93665c1d 100644
--- a/InfoScreen.h
+++ b/InfoScreen.h
@@ -36,16 +36,16 @@ struct InfoScreen_ {
    Vector* lines;
 };
 
-extern InfoScreen* InfoScreen_init(InfoScreen* this, Process* process, FunctionBar* bar, int height, const char* panelHeader);
+InfoScreen* InfoScreen_init(InfoScreen* this, Process* process, FunctionBar* bar, int height, const char* panelHeader);
 
-extern InfoScreen* InfoScreen_done(InfoScreen* this);
+InfoScreen* InfoScreen_done(InfoScreen* this);
 
-extern void InfoScreen_drawTitled(InfoScreen* this, const char* fmt, ...);
+void InfoScreen_drawTitled(InfoScreen* this, const char* fmt, ...);
 
-extern void InfoScreen_addLine(InfoScreen* this, const char* line);
+void InfoScreen_addLine(InfoScreen* this, const char* line);
 
-extern void InfoScreen_appendLine(InfoScreen* this, const char* line);
+void InfoScreen_appendLine(InfoScreen* this, const char* line);
 
-extern void InfoScreen_run(InfoScreen* this);
+void InfoScreen_run(InfoScreen* this);
 
 #endif
diff --git a/ListItem.h b/ListItem.h
index 3174df09..253f991c 100644
--- a/ListItem.h
+++ b/ListItem.h
@@ -19,12 +19,12 @@ typedef struct ListItem_ {
 
 extern ObjectClass ListItem_class;
 
-extern ListItem* ListItem_new(const char* value, int key);
+ListItem* ListItem_new(const char* value, int key);
 
-extern void ListItem_append(ListItem* this, const char* text);
+void ListItem_append(ListItem* this, const char* text);
 
-extern const char* ListItem_getRef(ListItem* this);
+const char* ListItem_getRef(ListItem* this);
 
-extern long ListItem_compare(const void* cast1, const void* cast2);
+long ListItem_compare(const void* cast1, const void* cast2);
 
 #endif
diff --git a/MainPanel.h b/MainPanel.h
index cf46a4ee..321f130c 100644
--- a/MainPanel.h
+++ b/MainPanel.h
@@ -25,22 +25,22 @@ typedef bool(*MainPanel_ForeachProcessFn)(Process*, Arg);
 #define MainPanel_getFunctionBar(this_) (((Panel*)(this_))->defaultBar)
 
 
-extern void MainPanel_updateTreeFunctions(MainPanel* this, bool mode);
+void MainPanel_updateTreeFunctions(MainPanel* this, bool mode);
 
-extern void MainPanel_pidSearch(MainPanel* this, int ch);
+void MainPanel_pidSearch(MainPanel* this, int ch);
 
-extern int MainPanel_selectedPid(MainPanel* this);
+int MainPanel_selectedPid(MainPanel* this);
 
-extern const char* MainPanel_getValue(MainPanel* this, int i);
+const char* MainPanel_getValue(MainPanel* this, int i);
 
-extern bool MainPanel_foreachProcess(MainPanel* this, MainPanel_ForeachProcessFn fn, Arg arg, bool* wasAnyTagged);
+bool MainPanel_foreachProcess(MainPanel* this, MainPanel_ForeachProcessFn fn, Arg arg, bool* wasAnyTagged);
 
 extern PanelClass MainPanel_class;
 
-extern MainPanel* MainPanel_new();
+MainPanel* MainPanel_new();
 
-extern void MainPanel_setState(MainPanel* this, State* state);
+void MainPanel_setState(MainPanel* this, State* state);
 
-extern void MainPanel_delete(Object* object);
+void MainPanel_delete(Object* object);
 
 #endif
diff --git a/Meter.h b/Meter.h
index 5596f3cc..1708a8ab 100644
--- a/Meter.h
+++ b/Meter.h
@@ -107,17 +107,17 @@ typedef struct GraphData_ {
 
 extern MeterClass Meter_class;
 
-extern Meter* Meter_new(struct ProcessList_* pl, int param, MeterClass* type);
+Meter* Meter_new(struct ProcessList_* pl, int param, MeterClass* type);
 
-extern int Meter_humanUnit(char* buffer, unsigned long int value, int size);
+int Meter_humanUnit(char* buffer, unsigned long int value, int size);
 
-extern void Meter_delete(Object* cast);
+void Meter_delete(Object* cast);
 
-extern void Meter_setCaption(Meter* this, const char* caption);
+void Meter_setCaption(Meter* this, const char* caption);
 
-extern void Meter_setMode(Meter* this, int modeIndex);
+void Meter_setMode(Meter* this, int modeIndex);
 
-extern ListItem* Meter_toListItem(Meter* this, bool moving);
+ListItem* Meter_toListItem(Meter* this, bool moving);
 
 /* ---------- TextMeterMode ---------- */
 
diff --git a/MetersPanel.h b/MetersPanel.h
index 111d6ef3..bea9238d 100644
--- a/MetersPanel.h
+++ b/MetersPanel.h
@@ -32,10 +32,10 @@ struct MetersPanel_ {
 // In <http://unicode.org/reports/tr11/>, arrows (U+2019..U+2199) are
 // considered "Ambiguous characters".
 
-extern void MetersPanel_setMoving(MetersPanel* this, bool moving);
+void MetersPanel_setMoving(MetersPanel* this, bool moving);
 
 extern PanelClass MetersPanel_class;
 
-extern MetersPanel* MetersPanel_new(Settings* settings, const char* header, Vector* meters, ScreenManager* scr);
+MetersPanel* MetersPanel_new(Settings* settings, const char* header, Vector* meters, ScreenManager* scr);
 
 #endif
diff --git a/Object.h b/Object.h
index 046447a7..f6874295 100644
--- a/Object.h
+++ b/Object.h
@@ -50,7 +50,7 @@ extern ObjectClass Object_class;
 
 #ifdef DEBUG
 
-extern bool Object_isA(Object* o, const ObjectClass* klass);
+bool Object_isA(Object* o, const ObjectClass* klass);
 
 #endif
 
diff --git a/OpenFilesScreen.h b/OpenFilesScreen.h
index 5f4d3574..9fc1216b 100644
--- a/OpenFilesScreen.h
+++ b/OpenFilesScreen.h
@@ -32,12 +32,12 @@ typedef struct OpenFilesScreen_ {
 
 extern InfoScreenClass OpenFilesScreen_class;
 
-extern OpenFilesScreen* OpenFilesScreen_new(Process* process);
+OpenFilesScreen* OpenFilesScreen_new(Process* process);
 
-extern void OpenFilesScreen_delete(Object* this);
+void OpenFilesScreen_delete(Object* this);
 
-extern void OpenFilesScreen_draw(InfoScreen* this);
+void OpenFilesScreen_draw(InfoScreen* this);
 
-extern void OpenFilesScreen_scan(InfoScreen* this);
+void OpenFilesScreen_scan(InfoScreen* this);
 
 #endif
diff --git a/Panel.h b/Panel.h
index aedc98b5..be8646ab 100644
--- a/Panel.h
+++ b/Panel.h
@@ -73,54 +73,54 @@ struct Panel_ {
 
 extern PanelClass Panel_class;
 
-extern Panel* Panel_new(int x, int y, int w, int h, bool owner, ObjectClass* type, FunctionBar* fuBar);
+Panel* Panel_new(int x, int y, int w, int h, bool owner, ObjectClass* type, FunctionBar* fuBar);
 
-extern void Panel_delete(Object* cast);
+void Panel_delete(Object* cast);
 
-extern void Panel_init(Panel* this, int x, int y, int w, int h, ObjectClass* type, bool owner, FunctionBar* fuBar);
+void Panel_init(Panel* this, int x, int y, int w, int h, ObjectClass* type, bool owner, FunctionBar* fuBar);
 
-extern void Panel_done(Panel* this);
+void Panel_done(Panel* this);
 
-extern void Panel_setSelectionColor(Panel* this, int color);
+void Panel_setSelectionColor(Panel* this, int color);
 
-extern RichString* Panel_getHeader(Panel* this);
+RichString* Panel_getHeader(Panel* this);
 
-extern void Panel_setHeader(Panel* this, const char* header);
+void Panel_setHeader(Panel* this, const char* header);
 
-extern void Panel_move(Panel* this, int x, int y);
+void Panel_move(Panel* this, int x, int y);
 
-extern void Panel_resize(Panel* this, int w, int h);
+void Panel_resize(Panel* this, int w, int h);
 
-extern void Panel_prune(Panel* this);
+void Panel_prune(Panel* this);
 
-extern void Panel_add(Panel* this, Object* o);
+void Panel_add(Panel* this, Object* o);
 
-extern void Panel_insert(Panel* this, int i, Object* o);
+void Panel_insert(Panel* this, int i, Object* o);
 
-extern void Panel_set(Panel* this, int i, Object* o);
+void Panel_set(Panel* this, int i, Object* o);
 
-extern Object* Panel_get(Panel* this, int i);
+Object* Panel_get(Panel* this, int i);
 
-extern Object* Panel_remove(Panel* this, int i);
+Object* Panel_remove(Panel* this, int i);
 
-extern Object* Panel_getSelected(Panel* this);
+Object* Panel_getSelected(Panel* this);
 
-extern void Panel_moveSelectedUp(Panel* this);
+void Panel_moveSelectedUp(Panel* this);
 
-extern void Panel_moveSelectedDown(Panel* this);
+void Panel_moveSelectedDown(Panel* this);
 
-extern int Panel_getSelectedIndex(Panel* this);
+int Panel_getSelectedIndex(Panel* this);
 
-extern int Panel_size(Panel* this);
+int Panel_size(Panel* this);
 
-extern void Panel_setSelected(Panel* this, int selected);
+void Panel_setSelected(Panel* this, int selected);
 
-extern void Panel_draw(Panel* this, bool focus);
+void Panel_draw(Panel* this, bool focus);
 
-extern void Panel_splice(Panel *this, Vector* from);
+void Panel_splice(Panel *this, Vector* from);
 
-extern bool Panel_onKey(Panel* this, int key);
+bool Panel_onKey(Panel* this, int key);
 
-extern HandlerResult Panel_selectByTyping(Panel* this, int ch);
+HandlerResult Panel_selectByTyping(Panel* this, int ch);
 
 #endif
diff --git a/Process.h b/Process.h
index d82724dd..9aca41c9 100644
--- a/Process.h
+++ b/Process.h
@@ -173,36 +173,36 @@ typedef struct ProcessClass_ {
 
 extern char Process_pidFormat[20];
 
-extern void Process_setupColumnWidths();
+void Process_setupColumnWidths();
 
-extern void Process_humanNumber(RichString* str, unsigned long number, bool coloring);
+void Process_humanNumber(RichString* str, unsigned long number, bool coloring);
 
-extern void Process_colorNumber(RichString* str, unsigned long long number, bool coloring);
+void Process_colorNumber(RichString* str, unsigned long long number, bool coloring);
 
-extern void Process_printTime(RichString* str, unsigned long long totalHundredths);
+void Process_printTime(RichString* str, unsigned long long totalHundredths);
 
-extern void Process_outputRate(RichString* str, char* buffer, int n, double rate, int coloring);
+void Process_outputRate(RichString* str, char* buffer, int n, double rate, int coloring);
 
-extern void Process_writeField(Process* this, RichString* str, ProcessField field);
+void Process_writeField(Process* this, RichString* str, ProcessField field);
 
-extern void Process_display(Object* cast, RichString* out);
+void Process_display(Object* cast, RichString* out);
 
-extern void Process_done(Process* this);
+void Process_done(Process* this);
 
 extern ProcessClass Process_class;
 
-extern void Process_init(Process* this, struct Settings_* settings);
+void Process_init(Process* this, struct Settings_* settings);
 
-extern void Process_toggleTag(Process* this);
+void Process_toggleTag(Process* this);
 
-extern bool Process_setPriority(Process* this, int priority);
+bool Process_setPriority(Process* this, int priority);
 
-extern bool Process_changePriorityBy(Process* this, Arg delta);
+bool Process_changePriorityBy(Process* this, Arg delta);
 
-extern bool Process_sendSignal(Process* this, Arg sgn);
+bool Process_sendSignal(Process* this, Arg sgn);
 
-extern long Process_pidCompare(const void* v1, const void* v2);
+long Process_pidCompare(const void* v1, const void* v2);
 
-extern long Process_compare(const void* v1, const void* v2);
+long Process_compare(const void* v1, const void* v2);
 
 #endif
diff --git a/ProcessList.h b/ProcessList.h
index 1a4170c0..73f6c687 100644
--- a/ProcessList.h
+++ b/ProcessList.h
@@ -69,32 +69,32 @@ void ProcessList_delete(ProcessList* pl);
 void ProcessList_goThroughEntries(ProcessList* pl);
 
 
-extern ProcessList* ProcessList_init(ProcessList* this, ObjectClass* klass, UsersTable* usersTable, Hashtable* pidWhiteList, uid_t userId);
+ProcessList* ProcessList_init(ProcessList* this, ObjectClass* klass, UsersTable* usersTable, Hashtable* pidWhiteList, uid_t userId);
 
-extern void ProcessList_done(ProcessList* this);
+void ProcessList_done(ProcessList* this);
 
-extern void ProcessList_setPanel(ProcessList* this, Panel* panel);
+void ProcessList_setPanel(ProcessList* this, Panel* panel);
 
-extern void ProcessList_printHeader(ProcessList* this, RichString* header);
+void ProcessList_printHeader(ProcessList* this, RichString* header);
 
-extern void ProcessList_add(ProcessList* this, Process* p);
+void ProcessList_add(ProcessList* this, Process* p);
 
-extern void ProcessList_remove(ProcessList* this, Process* p);
+void ProcessList_remove(ProcessList* this, Process* p);
 
-extern Process* ProcessList_get(ProcessList* this, int idx);
+Process* ProcessList_get(ProcessList* this, int idx);
 
-extern int ProcessList_size(ProcessList* this);
+int ProcessList_size(ProcessList* this);
 
-extern void ProcessList_sort(ProcessList* this);
+void ProcessList_sort(ProcessList* this);
 
-extern ProcessField ProcessList_keyAt(ProcessList* this, int at);
+ProcessField ProcessList_keyAt(ProcessList* this, int at);
 
-extern void ProcessList_expandTree(ProcessList* this);
+void ProcessList_expandTree(ProcessList* this);
 
-extern void ProcessList_rebuildPanel(ProcessList* this);
+void ProcessList_rebuildPanel(ProcessList* this);
 
-extern Process* ProcessList_getProcess(ProcessList* this, pid_t pid, bool* preExisting, Process_New constructor);
+Process* ProcessList_getProcess(ProcessList* this, pid_t pid, bool* preExisting, Process_New constructor);
 
-extern void ProcessList_scan(ProcessList* this);
+void ProcessList_scan(ProcessList* this);
 
 #endif
diff --git a/RichString.h b/RichString.h
index 824c0e2a..59b77496 100644
--- a/RichString.h
+++ b/RichString.h
@@ -67,26 +67,26 @@ typedef struct RichString_ {
 
 #ifdef HAVE_LIBNCURSESW
 
-extern void RichString_setAttrn(RichString* this, int attrs, int start, int finish);
+void RichString_setAttrn(RichString* this, int attrs, int start, int finish);
 
-extern int RichString_findChar(RichString* this, char c, int start);
+int RichString_findChar(RichString* this, char c, int start);
 
 #else
 
-extern void RichString_setAttrn(RichString* this, int attrs, int start, int finish);
+void RichString_setAttrn(RichString* this, int attrs, int start, int finish);
 
-extern int RichString_findChar(RichString* this, char c, int start);
+int RichString_findChar(RichString* this, char c, int start);
 
 #endif
 
-extern void RichString_prune(RichString* this);
+void RichString_prune(RichString* this);
 
-extern void RichString_setAttr(RichString* this, int attrs);
+void RichString_setAttr(RichString* this, int attrs);
 
-extern void RichString_append(RichString* this, int attrs, const char* data);
+void RichString_append(RichString* this, int attrs, const char* data);
 
-extern void RichString_appendn(RichString* this, int attrs, const char* data, int len);
+void RichString_appendn(RichString* this, int attrs, const char* data, int len);
 
-extern void RichString_write(RichString* this, int attrs, const char* data);
+void RichString_write(RichString* this, int attrs, const char* data);
 
 #endif
diff --git a/ScreenManager.h b/ScreenManager.h
index eaa90853..5907ce55 100644
--- a/ScreenManager.h
+++ b/ScreenManager.h
@@ -33,18 +33,18 @@ typedef struct ScreenManager_ {
 } ScreenManager;
 
 
-extern ScreenManager* ScreenManager_new(int x1, int y1, int x2, int y2, Orientation orientation, const Header* header, const Settings* settings, bool owner);
+ScreenManager* ScreenManager_new(int x1, int y1, int x2, int y2, Orientation orientation, const Header* header, const Settings* settings, bool owner);
 
-extern void ScreenManager_delete(ScreenManager* this);
+void ScreenManager_delete(ScreenManager* this);
 
-extern int ScreenManager_size(ScreenManager* this);
+int ScreenManager_size(ScreenManager* this);
 
-extern void ScreenManager_add(ScreenManager* this, Panel* item, int size);
+void ScreenManager_add(ScreenManager* this, Panel* item, int size);
 
-extern Panel* ScreenManager_remove(ScreenManager* this, int idx);
+Panel* ScreenManager_remove(ScreenManager* this, int idx);
 
-extern void ScreenManager_resize(ScreenManager* this, int x1, int y1, int x2, int y2);
+void ScreenManager_resize(ScreenManager* this, int x1, int y1, int x2, int y2);
 
-extern void ScreenManager_run(ScreenManager* this, Panel** lastFocus, int* lastKey);
+void ScreenManager_run(ScreenManager* this, Panel** lastFocus, int* lastKey);
 
 #endif
diff --git a/Settings.h b/Settings.h
index 23f5e7c1..63b6e8a3 100644
--- a/Settings.h
+++ b/Settings.h
@@ -63,12 +63,12 @@ typedef struct Settings_ {
 #endif
 
 
-extern void Settings_delete(Settings* this);
+void Settings_delete(Settings* this);
 
-extern bool Settings_write(Settings* this);
+bool Settings_write(Settings* this);
 
-extern Settings* Settings_new(int cpuCount);
+Settings* Settings_new(int cpuCount);
 
-extern void Settings_invertSortOrder(Settings* this);
+void Settings_invertSortOrder(Settings* this);
 
 #endif
diff --git a/SignalsPanel.h b/SignalsPanel.h
index a3991fd9..94077ed0 100644
--- a/SignalsPanel.h
+++ b/SignalsPanel.h
@@ -14,6 +14,6 @@ typedef struct SignalItem_ {
 } SignalItem;
 
 
-extern Panel* SignalsPanel_new();
+Panel* SignalsPanel_new();
 
 #endif
diff --git a/StringUtils.h b/StringUtils.h
index 0450f0df..cc0abb00 100644
--- a/StringUtils.h
+++ b/StringUtils.h
@@ -17,18 +17,18 @@ in the source distribution for its full text.
  * at compile time (e.g. when they are immutable string literals). :)
  */
 
-extern char* String_cat(const char* s1, const char* s2);
+char* String_cat(const char* s1, const char* s2);
 
-extern char* String_trim(const char* in);
+char* String_trim(const char* in);
 
-extern int String_eq(const char* s1, const char* s2);
+int String_eq(const char* s1, const char* s2);
 
-extern char** String_split(const char* s, char sep, int* n);
+char** String_split(const char* s, char sep, int* n);
 
-extern void String_freeArray(char** s);
+void String_freeArray(char** s);
 
-extern char* String_getToken(const char* line, const unsigned short int numMatch);
+char* String_getToken(const char* line, const unsigned short int numMatch);
 
-extern char* String_readLine(FILE* fd);
+char* String_readLine(FILE* fd);
 
 #endif
diff --git a/TraceScreen.h b/TraceScreen.h
index 18920405..1e5218c9 100644
--- a/TraceScreen.h
+++ b/TraceScreen.h
@@ -23,16 +23,16 @@ typedef struct TraceScreen_ {
 
 extern InfoScreenClass TraceScreen_class;
 
-extern TraceScreen* TraceScreen_new(Process* process);
+TraceScreen* TraceScreen_new(Process* process);
 
-extern void TraceScreen_delete(Object* cast);
+void TraceScreen_delete(Object* cast);
 
-extern void TraceScreen_draw(InfoScreen* this);
+void TraceScreen_draw(InfoScreen* this);
 
-extern bool TraceScreen_forkTracer(TraceScreen* this);
+bool TraceScreen_forkTracer(TraceScreen* this);
 
-extern void TraceScreen_updateTrace(InfoScreen* super);
+void TraceScreen_updateTrace(InfoScreen* super);
 
-extern bool TraceScreen_onKey(InfoScreen* super, int ch);
+bool TraceScreen_onKey(InfoScreen* super, int ch);
 
 #endif
diff --git a/UsersTable.h b/UsersTable.h
index 6113277f..fb3eaedd 100644
--- a/UsersTable.h
+++ b/UsersTable.h
@@ -13,12 +13,12 @@ typedef struct UsersTable_ {
    Hashtable* users;
 } UsersTable;
 
-extern UsersTable* UsersTable_new();
+UsersTable* UsersTable_new();
 
-extern void UsersTable_delete(UsersTable* this);
+void UsersTable_delete(UsersTable* this);
 
-extern char* UsersTable_getRef(UsersTable* this, unsigned int uid);
+char* UsersTable_getRef(UsersTable* this, unsigned int uid);
 
-extern void UsersTable_foreach(UsersTable* this, Hashtable_PairFunction f, void* userData);
+void UsersTable_foreach(UsersTable* this, Hashtable_PairFunction f, void* userData);
 
 #endif
diff --git a/Vector.h b/Vector.h
index 7286bf65..7d1436aa 100644
--- a/Vector.h
+++ b/Vector.h
@@ -25,42 +25,42 @@ typedef struct Vector_ {
 } Vector;
 
 
-extern Vector* Vector_new(ObjectClass* type, bool owner, int size);
+Vector* Vector_new(ObjectClass* type, bool owner, int size);
 
-extern void Vector_delete(Vector* this);
+void Vector_delete(Vector* this);
 
 #ifdef DEBUG
 
-extern int Vector_count(Vector* this);
+int Vector_count(Vector* this);
 
 #endif
 
-extern void Vector_prune(Vector* this);
+void Vector_prune(Vector* this);
 
 // If I were to use only one sorting algorithm for both cases, it would probably be this one:
 /*
 
 */
 
-extern void Vector_quickSort(Vector* this);
+void Vector_quickSort(Vector* this);
 
-extern void Vector_insertionSort(Vector* this);
+void Vector_insertionSort(Vector* this);
 
-extern void Vector_insert(Vector* this, int idx, void* data_);
+void Vector_insert(Vector* this, int idx, void* data_);
 
-extern Object* Vector_take(Vector* this, int idx);
+Object* Vector_take(Vector* this, int idx);
 
-extern Object* Vector_remove(Vector* this, int idx);
+Object* Vector_remove(Vector* this, int idx);
 
-extern void Vector_moveUp(Vector* this, int idx);
+void Vector_moveUp(Vector* this, int idx);
 
-extern void Vector_moveDown(Vector* this, int idx);
+void Vector_moveDown(Vector* this, int idx);
 
-extern void Vector_set(Vector* this, int idx, void* data_);
+void Vector_set(Vector* this, int idx, void* data_);
 
 #ifdef DEBUG
 
-extern Object* Vector_get(Vector* this, int idx);
+Object* Vector_get(Vector* this, int idx);
 
 #else
 
@@ -70,7 +70,7 @@ extern Object* Vector_get(Vector* this, int idx);
 
 #ifdef DEBUG
 
-extern int Vector_size(Vector* this);
+int Vector_size(Vector* this);
 
 #else
 
@@ -82,9 +82,9 @@ extern int Vector_size(Vector* this);
 
 */
 
-extern void Vector_add(Vector* this, void* data_);
+void Vector_add(Vector* this, void* data_);
 
-extern int Vector_indexOf(Vector* this, void* search_, Object_Compare compare);
+int Vector_indexOf(Vector* this, void* search_, Object_Compare compare);
 
 void Vector_splice(Vector* this, Vector* from);
 
diff --git a/XAlloc.h b/XAlloc.h
index f67bf0dc..b9334238 100644
--- a/XAlloc.h
+++ b/XAlloc.h
@@ -9,13 +9,13 @@
 #include <assert.h>
 #include <stdlib.h>
 
-extern void fail(void);
+void fail(void);
 
-extern void* xMalloc(size_t size);
+void* xMalloc(size_t size);
 
-extern void* xCalloc(size_t nmemb, size_t size);
+void* xCalloc(size_t nmemb, size_t size);
 
-extern void* xRealloc(void* ptr, size_t size);
+void* xRealloc(void* ptr, size_t size);
 
 #undef xAsprintf
 
@@ -36,9 +36,9 @@ extern void* xRealloc(void* ptr, size_t size);
 #endif
 #if (__has_attribute(nonnull) || \
     ((__GNUC__ > 3) || (__GNUC__ == 3 && __GNUC_MINOR__ >= 3)))
-extern char* xStrdup_(const char* str) __attribute__((nonnull));
+char* xStrdup_(const char* str) __attribute__((nonnull));
 #endif // __has_attribute(nonnull) || GNU C 3.3 or later
 
-extern char* xStrdup_(const char* str);
+char* xStrdup_(const char* str);
 
 #endif
diff --git a/freebsd/FreeBSDProcessList.h b/freebsd/FreeBSDProcessList.h
index d01659da..e00f25e9 100644
--- a/freebsd/FreeBSDProcessList.h
+++ b/freebsd/FreeBSDProcessList.h
@@ -55,14 +55,14 @@ typedef struct FreeBSDProcessList_ {
 extern char jail_errmsg[JAIL_ERRMSGLEN];
 
 
-extern ProcessList* ProcessList_new(UsersTable* usersTable, Hashtable* pidWhiteList, uid_t userId);
+ProcessList* ProcessList_new(UsersTable* usersTable, Hashtable* pidWhiteList, uid_t userId);
 
-extern void ProcessList_delete(ProcessList* this);
+void ProcessList_delete(ProcessList* this);
 
-extern char* FreeBSDProcessList_readProcessName(kvm_t* kd, struct kinfo_proc* kproc, int* basenameEnd);
+char* FreeBSDProcessList_readProcessName(kvm_t* kd, struct kinfo_proc* kproc, int* basenameEnd);
 
-extern char* FreeBSDProcessList_readJailName(struct kinfo_proc* kproc);
+char* FreeBSDProcessList_readJailName(struct kinfo_proc* kproc);
 
-extern void ProcessList_goThroughEntries(ProcessList* this);
+void ProcessList_goThroughEntries(ProcessList* this);
 
 #endif
diff --git a/htop.h b/htop.h
index ced66de2..c51f9650 100644
--- a/htop.h
+++ b/htop.h
@@ -12,6 +12,6 @@ in the source distribution for its full text.
 // ----------------------------------------
 
 
-extern int main(int argc, char** argv);
+int main(int argc, char** argv);
 
 #endif
diff --git a/linux/Battery.h b/linux/Battery.h
index d52b08c9..065895c5 100644
--- a/linux/Battery.h
+++ b/linux/Battery.h
@@ -27,6 +27,6 @@ Linux battery readings written by Ian P. Hands (iphands@gmail.com, ihands@redhat
 // READ FROM /sys
 // ----------------------------------------
 
-extern void Battery_getData(double* level, ACPresence* isOnAC);
+void Battery_getData(double* level, ACPresence* isOnAC);
 
 #endif
diff --git a/linux/IOPriorityPanel.h b/linux/IOPriorityPanel.h
index 5019d59a..04c1d43e 100644
--- a/linux/IOPriorityPanel.h
+++ b/linux/IOPriorityPanel.h
@@ -11,8 +11,8 @@ in the source distribution for its full text.
 #include "IOPriority.h"
 #include "ListItem.h"
 
-extern Panel* IOPriorityPanel_new(IOPriority currPrio);
+Panel* IOPriorityPanel_new(IOPriority currPrio);
 
-extern IOPriority IOPriorityPanel_getIOPriority(Panel* this);
+IOPriority IOPriorityPanel_getIOPriority(Panel* this);
 
 #endif
diff --git a/linux/LinuxCRT.h b/linux/LinuxCRT.h
index f4f8cf06..61304dac 100644
--- a/linux/LinuxCRT.h
+++ b/linux/LinuxCRT.h
@@ -10,6 +10,6 @@ in the source distribution for its full text.
 #ifdef HAVE_EXECINFO_H
 #endif
 
-extern void CRT_handleSIGSEGV(int sgn);
+void CRT_handleSIGSEGV(int sgn);
 
 #endif
diff --git a/linux/LinuxProcess.h b/linux/LinuxProcess.h
index 462ae6bc..8ee49f46 100644
--- a/linux/LinuxProcess.h
+++ b/linux/LinuxProcess.h
@@ -159,9 +159,9 @@ extern ProcessPidColumn Process_pidColumns[];
 
 extern ProcessClass LinuxProcess_class;
 
-extern LinuxProcess* LinuxProcess_new(Settings* settings);
+LinuxProcess* LinuxProcess_new(Settings* settings);
 
-extern void Process_delete(Object* cast);
+void Process_delete(Object* cast);
 
 /*
 [1] Note that before kernel 2.6.26 a process that has not asked for
@@ -173,18 +173,18 @@ extern io_priority;
 */
 #define LinuxProcess_effectiveIOPriority(p_) (IOPriority_class(p_->ioPriority) == IOPRIO_CLASS_NONE ? IOPriority_tuple(IOPRIO_CLASS_BE, (p_->super.nice + 20) / 5) : p_->ioPriority)
 
-extern IOPriority LinuxProcess_updateIOPriority(LinuxProcess* this);
+IOPriority LinuxProcess_updateIOPriority(LinuxProcess* this);
 
-extern bool LinuxProcess_setIOPriority(LinuxProcess* this, Arg ioprio);
+bool LinuxProcess_setIOPriority(LinuxProcess* this, Arg ioprio);
 
 #ifdef HAVE_DELAYACCT
-extern void LinuxProcess_printDelay(float delay_percent, char* buffer, int n);
+void LinuxProcess_printDelay(float delay_percent, char* buffer, int n);
 #endif
 
-extern void LinuxProcess_writeField(Process* this, RichString* str, ProcessField field);
+void LinuxProcess_writeField(Process* this, RichString* str, ProcessField field);
 
-extern long LinuxProcess_compare(const void* v1, const void* v2);
+long LinuxProcess_compare(const void* v1, const void* v2);
 
-extern bool Process_isThread(Process* this);
+bool Process_isThread(Process* this);
 
 #endif
diff --git a/linux/LinuxProcessList.h b/linux/LinuxProcessList.h
index 4a0e0206..b63f19aa 100644
--- a/linux/LinuxProcessList.h
+++ b/linux/LinuxProcessList.h
@@ -109,9 +109,9 @@ typedef struct LinuxProcessList_ {
 
 #endif
 
-extern ProcessList* ProcessList_new(UsersTable* usersTable, Hashtable* pidWhiteList, uid_t userId);
+ProcessList* ProcessList_new(UsersTable* usersTable, Hashtable* pidWhiteList, uid_t userId);
 
-extern void ProcessList_delete(ProcessList* pl);
+void ProcessList_delete(ProcessList* pl);
 
 
 #ifdef HAVE_TASKSTATS
@@ -134,6 +134,6 @@ extern void ProcessList_delete(ProcessList* pl);
 
 #endif
 
-extern void ProcessList_goThroughEntries(ProcessList* super);
+void ProcessList_goThroughEntries(ProcessList* super);
 
 #endif
diff --git a/linux/Platform.h b/linux/Platform.h
index ec685270..922a3392 100644
--- a/linux/Platform.h
+++ b/linux/Platform.h
@@ -25,27 +25,27 @@ extern const SignalItem Platform_signals[];
 
 extern const unsigned int Platform_numberOfSignals;
 
-extern void Platform_setBindings(Htop_Action* keys);
+void Platform_setBindings(Htop_Action* keys);
 
 extern MeterClass* Platform_meterTypes[];
 
-extern int Platform_getUptime();
+int Platform_getUptime();
 
-extern void Platform_getLoadAverage(double* one, double* five, double* fifteen);
+void Platform_getLoadAverage(double* one, double* five, double* fifteen);
 
-extern int Platform_getMaxPid();
+int Platform_getMaxPid();
 
-extern double Platform_setCPUValues(Meter* this, int cpu);
+double Platform_setCPUValues(Meter* this, int cpu);
 
-extern void Platform_setMemoryValues(Meter* this);
+void Platform_setMemoryValues(Meter* this);
 
-extern void Platform_setSwapValues(Meter* this);
+void Platform_setSwapValues(Meter* this);
 
-extern void Platform_setZfsArcValues(Meter* this);
+void Platform_setZfsArcValues(Meter* this);
 
-extern void Platform_setZfsCompressedArcValues(Meter* this);
-extern char* Platform_getProcessEnv(pid_t pid);
+void Platform_setZfsCompressedArcValues(Meter* this);
+char* Platform_getProcessEnv(pid_t pid);
 
-extern void Platform_getPressureStall(const char *file, bool some, double* ten, double* sixty, double* threehundred);
+void Platform_getPressureStall(const char *file, bool some, double* ten, double* sixty, double* threehundred);
 
 #endif
diff --git a/zfs/ZfsArcMeter.h b/zfs/ZfsArcMeter.h
index f2e322f9..c52083df 100644
--- a/zfs/ZfsArcMeter.h
+++ b/zfs/ZfsArcMeter.h
@@ -15,7 +15,7 @@ in the source distribution for its full text.
 
 extern int ZfsArcMeter_attributes[];
 
-extern void ZfsArcMeter_readStats(Meter* this, ZfsArcStats* stats);
+void ZfsArcMeter_readStats(Meter* this, ZfsArcStats* stats);
 
 extern MeterClass ZfsArcMeter_class;