diff --git a/AffinityPanel.c b/AffinityPanel.c
index 6c64b14b..127623c6 100644
--- a/AffinityPanel.c
+++ b/AffinityPanel.c
@@ -319,7 +319,7 @@ static MaskItem *AffinityPanel_buildTopology(AffinityPanel* this, hwloc_obj_t ob
 
 #endif
 
-PanelClass AffinityPanel_class = {
+const PanelClass AffinityPanel_class = {
    .super = {
       .extends = Class(Panel),
       .delete = AffinityPanel_delete
diff --git a/AffinityPanel.h b/AffinityPanel.h
index 37c7e5d9..fdefeae4 100644
--- a/AffinityPanel.h
+++ b/AffinityPanel.h
@@ -11,7 +11,7 @@ in the source distribution for its full text.
 #include "Affinity.h"
 #include "ProcessList.h"
 
-extern PanelClass AffinityPanel_class;
+extern const PanelClass AffinityPanel_class;
 
 Panel* AffinityPanel_new(ProcessList* pl, Affinity* affinity, int* width);
 
diff --git a/AvailableColumnsPanel.c b/AvailableColumnsPanel.c
index fd247af0..dcfbb3e2 100644
--- a/AvailableColumnsPanel.c
+++ b/AvailableColumnsPanel.c
@@ -57,7 +57,7 @@ static HandlerResult AvailableColumnsPanel_eventHandler(Panel* super, int ch) {
    return result;
 }
 
-PanelClass AvailableColumnsPanel_class = {
+const PanelClass AvailableColumnsPanel_class = {
    .super = {
       .extends = Class(Panel),
       .delete = AvailableColumnsPanel_delete
diff --git a/AvailableColumnsPanel.h b/AvailableColumnsPanel.h
index dd011755..8672eb9e 100644
--- a/AvailableColumnsPanel.h
+++ b/AvailableColumnsPanel.h
@@ -14,7 +14,7 @@ typedef struct AvailableColumnsPanel_ {
    Panel* columns;
 } AvailableColumnsPanel;
 
-extern PanelClass AvailableColumnsPanel_class;
+extern const PanelClass AvailableColumnsPanel_class;
 
 AvailableColumnsPanel* AvailableColumnsPanel_new(Panel* columns);
 
diff --git a/AvailableMetersPanel.c b/AvailableMetersPanel.c
index f5e59218..812d1f3d 100644
--- a/AvailableMetersPanel.c
+++ b/AvailableMetersPanel.c
@@ -24,7 +24,7 @@ static void AvailableMetersPanel_delete(Object* object) {
    free(this);
 }
 
-static inline void AvailableMetersPanel_addMeter(Header* header, Panel* panel, MeterClass* type, int param, int column) {
+static inline void AvailableMetersPanel_addMeter(Header* header, Panel* panel, const MeterClass* type, int param, int column) {
    Meter* meter = Header_addMeterByClass(header, type, param, column);
    Panel_add(panel, (Object*) Meter_toListItem(meter, false));
    Panel_setSelected(panel, Panel_size(panel) - 1);
@@ -77,7 +77,7 @@ static HandlerResult AvailableMetersPanel_eventHandler(Panel* super, int ch) {
    return result;
 }
 
-PanelClass AvailableMetersPanel_class = {
+const PanelClass AvailableMetersPanel_class = {
    .super = {
       .extends = Class(Panel),
       .delete = AvailableMetersPanel_delete
@@ -101,13 +101,13 @@ AvailableMetersPanel* AvailableMetersPanel_new(Settings* settings, Header* heade
    // Platform_meterTypes[0] should be always (&CPUMeter_class), which we will
    // handle separately in the code below.
    for (int i = 1; Platform_meterTypes[i]; i++) {
-      MeterClass* type = Platform_meterTypes[i];
+      const MeterClass* type = Platform_meterTypes[i];
       assert(type != &CPUMeter_class);
       const char* label = type->description ? type->description : type->uiName;
       Panel_add(super, (Object*) ListItem_new(label, i << 16));
    }
    // Handle (&CPUMeter_class)
-   MeterClass* type = &CPUMeter_class;
+   const MeterClass* type = &CPUMeter_class;
    int cpus = pl->cpuCount;
    if (cpus > 1) {
       Panel_add(super, (Object*) ListItem_new("CPU average", 0));
diff --git a/AvailableMetersPanel.h b/AvailableMetersPanel.h
index f4f18dac..f168869d 100644
--- a/AvailableMetersPanel.h
+++ b/AvailableMetersPanel.h
@@ -22,7 +22,7 @@ typedef struct AvailableMetersPanel_ {
    Panel* rightPanel;
 } AvailableMetersPanel;
 
-extern PanelClass AvailableMetersPanel_class;
+extern const PanelClass AvailableMetersPanel_class;
 
 AvailableMetersPanel* AvailableMetersPanel_new(Settings* settings, Header* header, Panel* leftMeters, Panel* rightMeters, ScreenManager* scr, ProcessList* pl);
 
diff --git a/BatteryMeter.c b/BatteryMeter.c
index 4f119e1f..060b125c 100644
--- a/BatteryMeter.c
+++ b/BatteryMeter.c
@@ -58,7 +58,7 @@ static void BatteryMeter_updateValues(Meter * this, char *buffer, int len) {
    }
 }
 
-MeterClass BatteryMeter_class = {
+const MeterClass BatteryMeter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete
diff --git a/BatteryMeter.h b/BatteryMeter.h
index 8f9441cc..b6e8c520 100644
--- a/BatteryMeter.h
+++ b/BatteryMeter.h
@@ -17,6 +17,6 @@ typedef enum ACPresence_ {
    AC_ERROR
 } ACPresence;
 
-extern MeterClass BatteryMeter_class;
+extern const MeterClass BatteryMeter_class;
 
 #endif
diff --git a/CPUMeter.c b/CPUMeter.c
index 72988472..7ce6caf8 100644
--- a/CPUMeter.c
+++ b/CPUMeter.c
@@ -246,7 +246,7 @@ static void SingleColCPUsMeter_draw(Meter* this, int x, int y, int w) {
 }
 
 
-MeterClass CPUMeter_class = {
+const MeterClass CPUMeter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete,
@@ -263,7 +263,7 @@ MeterClass CPUMeter_class = {
    .init = CPUMeter_init
 };
 
-MeterClass AllCPUsMeter_class = {
+const MeterClass AllCPUsMeter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete,
@@ -282,7 +282,7 @@ MeterClass AllCPUsMeter_class = {
    .done = AllCPUsMeter_done
 };
 
-MeterClass AllCPUs2Meter_class = {
+const MeterClass AllCPUs2Meter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete,
@@ -301,7 +301,7 @@ MeterClass AllCPUs2Meter_class = {
    .done = AllCPUsMeter_done
 };
 
-MeterClass LeftCPUsMeter_class = {
+const MeterClass LeftCPUsMeter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete,
@@ -320,7 +320,7 @@ MeterClass LeftCPUsMeter_class = {
    .done = AllCPUsMeter_done
 };
 
-MeterClass RightCPUsMeter_class = {
+const MeterClass RightCPUsMeter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete,
@@ -339,7 +339,7 @@ MeterClass RightCPUsMeter_class = {
    .done = AllCPUsMeter_done
 };
 
-MeterClass LeftCPUs2Meter_class = {
+const MeterClass LeftCPUs2Meter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete,
@@ -358,7 +358,7 @@ MeterClass LeftCPUs2Meter_class = {
    .done = AllCPUsMeter_done
 };
 
-MeterClass RightCPUs2Meter_class = {
+const MeterClass RightCPUs2Meter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete,
@@ -377,7 +377,7 @@ MeterClass RightCPUs2Meter_class = {
    .done = AllCPUsMeter_done
 };
 
-MeterClass AllCPUs4Meter_class = {
+const MeterClass AllCPUs4Meter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete,
@@ -396,7 +396,7 @@ MeterClass AllCPUs4Meter_class = {
    .done = AllCPUsMeter_done
 };
 
-MeterClass LeftCPUs4Meter_class = {
+const MeterClass LeftCPUs4Meter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete,
@@ -415,7 +415,7 @@ MeterClass LeftCPUs4Meter_class = {
    .done = AllCPUsMeter_done
 };
 
-MeterClass RightCPUs4Meter_class = {
+const MeterClass RightCPUs4Meter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete,
@@ -434,7 +434,7 @@ MeterClass RightCPUs4Meter_class = {
    .done = AllCPUsMeter_done
 };
 
-MeterClass AllCPUs8Meter_class = {
+const MeterClass AllCPUs8Meter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete,
@@ -453,7 +453,7 @@ MeterClass AllCPUs8Meter_class = {
    .done = AllCPUsMeter_done
 };
 
-MeterClass LeftCPUs8Meter_class = {
+const MeterClass LeftCPUs8Meter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete,
@@ -472,7 +472,7 @@ MeterClass LeftCPUs8Meter_class = {
    .done = AllCPUsMeter_done
 };
 
-MeterClass RightCPUs8Meter_class = {
+const MeterClass RightCPUs8Meter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete,
diff --git a/CPUMeter.h b/CPUMeter.h
index 471f33fc..d60e82f7 100644
--- a/CPUMeter.h
+++ b/CPUMeter.h
@@ -22,30 +22,30 @@ typedef enum {
    CPU_METER_ITEMCOUNT = 9, // number of entries in this enum
 } CPUMeterValues;
 
-extern MeterClass CPUMeter_class;
+extern const MeterClass CPUMeter_class;
 
-extern MeterClass AllCPUsMeter_class;
+extern const MeterClass AllCPUsMeter_class;
 
-extern MeterClass AllCPUs2Meter_class;
+extern const MeterClass AllCPUs2Meter_class;
 
-extern MeterClass LeftCPUsMeter_class;
+extern const MeterClass LeftCPUsMeter_class;
 
-extern MeterClass RightCPUsMeter_class;
+extern const MeterClass RightCPUsMeter_class;
 
-extern MeterClass LeftCPUs2Meter_class;
+extern const MeterClass LeftCPUs2Meter_class;
 
-extern MeterClass RightCPUs2Meter_class;
+extern const MeterClass RightCPUs2Meter_class;
 
-extern MeterClass AllCPUs4Meter_class;
+extern const MeterClass AllCPUs4Meter_class;
 
-extern MeterClass LeftCPUs4Meter_class;
+extern const MeterClass LeftCPUs4Meter_class;
 
-extern MeterClass RightCPUs4Meter_class;
+extern const MeterClass RightCPUs4Meter_class;
 
-extern MeterClass AllCPUs8Meter_class;
+extern const MeterClass AllCPUs8Meter_class;
 
-extern MeterClass LeftCPUs8Meter_class;
+extern const MeterClass LeftCPUs8Meter_class;
 
-extern MeterClass RightCPUs8Meter_class;
+extern const MeterClass RightCPUs8Meter_class;
 
 #endif
diff --git a/CategoriesPanel.c b/CategoriesPanel.c
index b09a015f..8adf14f6 100644
--- a/CategoriesPanel.c
+++ b/CategoriesPanel.c
@@ -109,7 +109,7 @@ static HandlerResult CategoriesPanel_eventHandler(Panel* super, int ch) {
    return result;
 }
 
-PanelClass CategoriesPanel_class = {
+const PanelClass CategoriesPanel_class = {
    .super = {
       .extends = Class(Panel),
       .delete = CategoriesPanel_delete
diff --git a/CategoriesPanel.h b/CategoriesPanel.h
index 891d7711..1f17bd2e 100644
--- a/CategoriesPanel.h
+++ b/CategoriesPanel.h
@@ -23,7 +23,7 @@ typedef struct CategoriesPanel_ {
 
 void CategoriesPanel_makeMetersPage(CategoriesPanel* this);
 
-extern PanelClass CategoriesPanel_class;
+extern const PanelClass CategoriesPanel_class;
 
 CategoriesPanel* CategoriesPanel_new(ScreenManager* scr, Settings* settings, Header* header, ProcessList* pl);
 
diff --git a/CheckItem.c b/CheckItem.c
index f6d5bb91..09e42ee6 100644
--- a/CheckItem.c
+++ b/CheckItem.c
@@ -33,7 +33,7 @@ static void CheckItem_display(Object* cast, RichString* out) {
    RichString_append(out, CRT_colors[CHECK_TEXT], this->text);
 }
 
-ObjectClass CheckItem_class = {
+const ObjectClass CheckItem_class = {
    .display = CheckItem_display,
    .delete = CheckItem_delete
 };
diff --git a/CheckItem.h b/CheckItem.h
index 71483526..168efdcc 100644
--- a/CheckItem.h
+++ b/CheckItem.h
@@ -16,7 +16,7 @@ typedef struct CheckItem_ {
    bool value;
 } CheckItem;
 
-extern ObjectClass CheckItem_class;
+extern const ObjectClass CheckItem_class;
 
 CheckItem* CheckItem_newByRef(char* text, bool* ref);
 
diff --git a/ClockMeter.c b/ClockMeter.c
index d309852f..51fbed63 100644
--- a/ClockMeter.c
+++ b/ClockMeter.c
@@ -24,7 +24,7 @@ static void ClockMeter_updateValues(Meter* this, char* buffer, int size) {
    strftime(buffer, size, "%H:%M:%S", lt);
 }
 
-MeterClass ClockMeter_class = {
+const MeterClass ClockMeter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete
diff --git a/ClockMeter.h b/ClockMeter.h
index e431e367..ecd4b6a9 100644
--- a/ClockMeter.h
+++ b/ClockMeter.h
@@ -9,6 +9,6 @@ in the source distribution for its full text.
 
 #include "Meter.h"
 
-extern MeterClass ClockMeter_class;
+extern const MeterClass ClockMeter_class;
 
 #endif
diff --git a/ColorsPanel.c b/ColorsPanel.c
index 36cd85bd..75d3e654 100644
--- a/ColorsPanel.c
+++ b/ColorsPanel.c
@@ -76,7 +76,7 @@ static HandlerResult ColorsPanel_eventHandler(Panel* super, int ch) {
    return result;
 }
 
-PanelClass ColorsPanel_class = {
+const PanelClass ColorsPanel_class = {
    .super = {
       .extends = Class(Panel),
       .delete = ColorsPanel_delete
diff --git a/ColorsPanel.h b/ColorsPanel.h
index 0f69e8f7..f63ca356 100644
--- a/ColorsPanel.h
+++ b/ColorsPanel.h
@@ -18,7 +18,7 @@ typedef struct ColorsPanel_ {
    ScreenManager* scr;
 } ColorsPanel;
 
-extern PanelClass ColorsPanel_class;
+extern const PanelClass ColorsPanel_class;
 
 ColorsPanel* ColorsPanel_new(Settings* settings, ScreenManager* scr);
 
diff --git a/ColumnsPanel.c b/ColumnsPanel.c
index 8328d15e..e4fe4fc1 100644
--- a/ColumnsPanel.c
+++ b/ColumnsPanel.c
@@ -105,7 +105,7 @@ static HandlerResult ColumnsPanel_eventHandler(Panel* super, int ch) {
    return result;
 }
 
-PanelClass ColumnsPanel_class = {
+const PanelClass ColumnsPanel_class = {
    .super = {
       .extends = Class(Panel),
       .delete = ColumnsPanel_delete
diff --git a/ColumnsPanel.h b/ColumnsPanel.h
index a35036f1..e8acbb23 100644
--- a/ColumnsPanel.h
+++ b/ColumnsPanel.h
@@ -17,7 +17,7 @@ typedef struct ColumnsPanel_ {
    bool moving;
 } ColumnsPanel;
 
-extern PanelClass ColumnsPanel_class;
+extern const PanelClass ColumnsPanel_class;
 
 ColumnsPanel* ColumnsPanel_new(Settings* settings);
 
diff --git a/CommandScreen.c b/CommandScreen.c
index bc71e09f..58ed8840 100644
--- a/CommandScreen.c
+++ b/CommandScreen.c
@@ -48,7 +48,7 @@ static void CommandScreen_draw(InfoScreen* this) {
    InfoScreen_drawTitled(this, "Command of process %d - %s", this->process->pid, this->process->comm);
 }
 
-InfoScreenClass CommandScreen_class = {
+const InfoScreenClass CommandScreen_class = {
    .super = {
       .extends = Class(Object),
       .delete = CommandScreen_delete
diff --git a/CommandScreen.h b/CommandScreen.h
index a1604a3e..4f3ce947 100644
--- a/CommandScreen.h
+++ b/CommandScreen.h
@@ -7,7 +7,7 @@ typedef struct CommandScreen_ {
    InfoScreen super;
 } CommandScreen;
 
-extern InfoScreenClass CommandScreen_class;
+extern const InfoScreenClass CommandScreen_class;
 
 CommandScreen* CommandScreen_new(Process* process);
 
diff --git a/DateMeter.c b/DateMeter.c
index e130159a..6ea108e1 100644
--- a/DateMeter.c
+++ b/DateMeter.c
@@ -31,7 +31,7 @@ static void DateMeter_updateValues(Meter* this, char* buffer, int size) {
    strftime(buffer, size, "%F", lt);
 }
 
-MeterClass DateMeter_class = {
+const MeterClass DateMeter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete
diff --git a/DateMeter.h b/DateMeter.h
index 44ed24da..63455767 100644
--- a/DateMeter.h
+++ b/DateMeter.h
@@ -9,6 +9,6 @@ in the source distribution for its full text.
 
 #include "Meter.h"
 
-extern MeterClass DateMeter_class;
+extern const MeterClass DateMeter_class;
 
 #endif
diff --git a/DateTimeMeter.c b/DateTimeMeter.c
index 32dd5d1a..f3c877b3 100644
--- a/DateTimeMeter.c
+++ b/DateTimeMeter.c
@@ -31,7 +31,7 @@ static void DateTimeMeter_updateValues(Meter* this, char* buffer, int size) {
    strftime(buffer, size, "%F %H:%M:%S", lt);
 }
 
-MeterClass DateTimeMeter_class = {
+const MeterClass DateTimeMeter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete
diff --git a/DateTimeMeter.h b/DateTimeMeter.h
index ef25264c..6cb73c24 100644
--- a/DateTimeMeter.h
+++ b/DateTimeMeter.h
@@ -9,6 +9,6 @@ in the source distribution for its full text.
 
 #include "Meter.h"
 
-extern MeterClass DateTimeMeter_class;
+extern const MeterClass DateTimeMeter_class;
 
 #endif
diff --git a/DiskIOMeter.c b/DiskIOMeter.c
index 1349bf40..781d9bb6 100644
--- a/DiskIOMeter.c
+++ b/DiskIOMeter.c
@@ -75,7 +75,7 @@ static void DIskIOMeter_display(ATTR_UNUSED Object* cast, RichString* out) {
    RichString_append(out, CRT_colors[DISKIO_WRITE], buffer);
 }
 
-MeterClass DiskIOMeter_class = {
+const MeterClass DiskIOMeter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete,
diff --git a/DiskIOMeter.h b/DiskIOMeter.h
index f75aaf81..c7e4542a 100644
--- a/DiskIOMeter.h
+++ b/DiskIOMeter.h
@@ -9,6 +9,6 @@ in the source distribution for its full text.
 
 #include "Meter.h"
 
-extern MeterClass DiskIOMeter_class;
+extern const MeterClass DiskIOMeter_class;
 
 #endif /* HEADER_DiskIOMeter */
diff --git a/DisplayOptionsPanel.c b/DisplayOptionsPanel.c
index 54b389ba..1aede655 100644
--- a/DisplayOptionsPanel.c
+++ b/DisplayOptionsPanel.c
@@ -52,7 +52,7 @@ static HandlerResult DisplayOptionsPanel_eventHandler(Panel* super, int ch) {
    return result;
 }
 
-PanelClass DisplayOptionsPanel_class = {
+const PanelClass DisplayOptionsPanel_class = {
    .super = {
       .extends = Class(Panel),
       .delete = DisplayOptionsPanel_delete
diff --git a/DisplayOptionsPanel.h b/DisplayOptionsPanel.h
index aad7bc75..02b67a08 100644
--- a/DisplayOptionsPanel.h
+++ b/DisplayOptionsPanel.h
@@ -18,7 +18,7 @@ typedef struct DisplayOptionsPanel_ {
    ScreenManager* scr;
 } DisplayOptionsPanel;
 
-extern PanelClass DisplayOptionsPanel_class;
+extern const PanelClass DisplayOptionsPanel_class;
 
 DisplayOptionsPanel* DisplayOptionsPanel_new(Settings* settings, ScreenManager* scr);
 
diff --git a/EnvScreen.c b/EnvScreen.c
index 479a45d6..1f107457 100644
--- a/EnvScreen.c
+++ b/EnvScreen.c
@@ -12,7 +12,7 @@
 #include <unistd.h>
 
 
-InfoScreenClass EnvScreen_class = {
+const InfoScreenClass EnvScreen_class = {
    .super = {
       .extends = Class(Object),
       .delete = EnvScreen_delete
diff --git a/EnvScreen.h b/EnvScreen.h
index 54dfa41a..428a121f 100644
--- a/EnvScreen.h
+++ b/EnvScreen.h
@@ -7,7 +7,7 @@ typedef struct EnvScreen_ {
    InfoScreen super;
 } EnvScreen;
 
-extern InfoScreenClass EnvScreen_class;
+extern const InfoScreenClass EnvScreen_class;
 
 EnvScreen* EnvScreen_new(Process* process);
 
diff --git a/Header.c b/Header.c
index 7a58c4c2..e5a64db1 100644
--- a/Header.c
+++ b/Header.c
@@ -88,7 +88,7 @@ MeterModeId Header_addMeterByName(Header* this, char* name, int column) {
       *paren = '\0';
    }
    MeterModeId mode = TEXT_METERMODE;
-   for (MeterClass** type = Platform_meterTypes; *type; type++) {
+   for (const MeterClass* const* type = Platform_meterTypes; *type; type++) {
       if (String_eq(name, (*type)->name)) {
          Meter* meter = Meter_new(this->pl, param, *type);
          Vector_add(meters, meter);
@@ -110,7 +110,7 @@ void Header_setMode(Header* this, int i, MeterModeId mode, int column) {
    Meter_setMode(meter, mode);
 }
 
-Meter* Header_addMeterByClass(Header* this, MeterClass* type, int param, int column) {
+Meter* Header_addMeterByClass(Header* this, const MeterClass* type, int param, int column) {
    Vector* meters = this->columns[column];
 
    Meter* meter = Meter_new(this->pl, param, type);
diff --git a/Header.h b/Header.h
index 2637dc99..9059a9f4 100644
--- a/Header.h
+++ b/Header.h
@@ -34,7 +34,7 @@ MeterModeId Header_addMeterByName(Header* this, char* name, int column);
 
 void Header_setMode(Header* this, int i, MeterModeId mode, int column);
 
-Meter* Header_addMeterByClass(Header* this, MeterClass* type, int param, int column);
+Meter* Header_addMeterByClass(Header* this, const MeterClass* type, int param, int column);
 
 int Header_size(Header* this, int column);
 
diff --git a/HostnameMeter.c b/HostnameMeter.c
index 4d39a39a..24424d01 100644
--- a/HostnameMeter.c
+++ b/HostnameMeter.c
@@ -21,7 +21,7 @@ static void HostnameMeter_updateValues(Meter* this, char* buffer, int size) {
    gethostname(buffer, size-1);
 }
 
-MeterClass HostnameMeter_class = {
+const MeterClass HostnameMeter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete
diff --git a/HostnameMeter.h b/HostnameMeter.h
index c868512b..77fe3da9 100644
--- a/HostnameMeter.h
+++ b/HostnameMeter.h
@@ -9,6 +9,6 @@ in the source distribution for its full text.
 
 #include "Meter.h"
 
-extern MeterClass HostnameMeter_class;
+extern const MeterClass HostnameMeter_class;
 
 #endif
diff --git a/ListItem.c b/ListItem.c
index 20644467..e1dcd52d 100644
--- a/ListItem.c
+++ b/ListItem.c
@@ -42,7 +42,7 @@ static void ListItem_display(Object* cast, RichString* out) {
    RichString_append(out, CRT_colors[DEFAULT_COLOR], this->value/*buffer*/);
 }
 
-ObjectClass ListItem_class = {
+const ObjectClass ListItem_class = {
    .display = ListItem_display,
    .delete = ListItem_delete,
    .compare = ListItem_compare
diff --git a/ListItem.h b/ListItem.h
index 8e76ff7e..387e8e21 100644
--- a/ListItem.h
+++ b/ListItem.h
@@ -16,7 +16,7 @@ typedef struct ListItem_ {
    bool moving;
 } ListItem;
 
-extern ObjectClass ListItem_class;
+extern const ObjectClass ListItem_class;
 
 ListItem* ListItem_new(const char* value, int key);
 
diff --git a/LoadAverageMeter.c b/LoadAverageMeter.c
index d14d97ab..d2fa582a 100644
--- a/LoadAverageMeter.c
+++ b/LoadAverageMeter.c
@@ -53,7 +53,7 @@ static void LoadMeter_display(Object* cast, RichString* out) {
    RichString_write(out, CRT_colors[LOAD], buffer);
 }
 
-MeterClass LoadAverageMeter_class = {
+const MeterClass LoadAverageMeter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete,
@@ -70,7 +70,7 @@ MeterClass LoadAverageMeter_class = {
    .caption = "Load average: "
 };
 
-MeterClass LoadMeter_class = {
+const MeterClass LoadMeter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete,
diff --git a/LoadAverageMeter.h b/LoadAverageMeter.h
index 44230693..776c8bf6 100644
--- a/LoadAverageMeter.h
+++ b/LoadAverageMeter.h
@@ -9,8 +9,8 @@ in the source distribution for its full text.
 
 #include "Meter.h"
 
-extern MeterClass LoadAverageMeter_class;
+extern const MeterClass LoadAverageMeter_class;
 
-extern MeterClass LoadMeter_class;
+extern const MeterClass LoadMeter_class;
 
 #endif
diff --git a/MainPanel.c b/MainPanel.c
index 51bcf1ae..604749a9 100644
--- a/MainPanel.c
+++ b/MainPanel.c
@@ -150,7 +150,7 @@ bool MainPanel_foreachProcess(MainPanel* this, MainPanel_ForeachProcessFn fn, Ar
    return ok;
 }
 
-PanelClass MainPanel_class = {
+const PanelClass MainPanel_class = {
    .super = {
       .extends = Class(Panel),
       .delete = MainPanel_delete
diff --git a/MainPanel.h b/MainPanel.h
index 72790d3c..9e2da305 100644
--- a/MainPanel.h
+++ b/MainPanel.h
@@ -34,7 +34,7 @@ const char* MainPanel_getValue(MainPanel* this, int i);
 
 bool MainPanel_foreachProcess(MainPanel* this, MainPanel_ForeachProcessFn fn, Arg arg, bool* wasAnyTagged);
 
-extern PanelClass MainPanel_class;
+extern const PanelClass MainPanel_class;
 
 MainPanel* MainPanel_new(void);
 
diff --git a/MemoryMeter.c b/MemoryMeter.c
index 5834e507..fa0e09ab 100644
--- a/MemoryMeter.c
+++ b/MemoryMeter.c
@@ -53,7 +53,7 @@ static void MemoryMeter_display(Object* cast, RichString* out) {
    RichString_append(out, CRT_colors[MEMORY_CACHE], buffer);
 }
 
-MeterClass MemoryMeter_class = {
+const MeterClass MemoryMeter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete,
diff --git a/MemoryMeter.h b/MemoryMeter.h
index c490b143..d299483a 100644
--- a/MemoryMeter.h
+++ b/MemoryMeter.h
@@ -9,6 +9,6 @@ in the source distribution for its full text.
 
 #include "Meter.h"
 
-extern MeterClass MemoryMeter_class;
+extern const MeterClass MemoryMeter_class;
 
 #endif
diff --git a/Meter.c b/Meter.c
index cd6d089f..15be309f 100644
--- a/Meter.c
+++ b/Meter.c
@@ -21,7 +21,7 @@ in the source distribution for its full text.
 
 #define GRAPH_HEIGHT 4 /* Unit: rows (lines) */
 
-MeterClass Meter_class = {
+const MeterClass Meter_class = {
    .super = {
       .extends = Class(Object)
    }
@@ -115,7 +115,7 @@ void Meter_setMode(Meter* this, int modeIndex) {
       free(this->drawData);
       this->drawData = NULL;
 
-      MeterMode* mode = Meter_modes[modeIndex];
+      const MeterMode* mode = Meter_modes[modeIndex];
       this->draw = mode->draw;
       this->h = mode->h;
    }
@@ -410,7 +410,7 @@ static MeterMode LEDMeterMode = {
    .draw = LEDMeterMode_draw,
 };
 
-MeterMode* Meter_modes[] = {
+const MeterMode* const Meter_modes[] = {
    NULL,
    &BarMeterMode,
    &TextMeterMode,
@@ -437,7 +437,7 @@ static const int BlankMeter_attributes[] = {
    DEFAULT_COLOR
 };
 
-MeterClass BlankMeter_class = {
+const MeterClass BlankMeter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete,
diff --git a/Meter.h b/Meter.h
index 34f388f4..0647c764 100644
--- a/Meter.h
+++ b/Meter.h
@@ -88,7 +88,7 @@ typedef struct GraphData_ {
    double values[METER_BUFFER_LEN];
 } GraphData;
 
-extern MeterClass Meter_class;
+extern const MeterClass Meter_class;
 
 Meter* Meter_new(struct ProcessList_* pl, int param, const MeterClass* type);
 
@@ -102,8 +102,8 @@ void Meter_setMode(Meter* this, int modeIndex);
 
 ListItem* Meter_toListItem(Meter* this, bool moving);
 
-extern MeterMode* Meter_modes[];
+extern const MeterMode* const Meter_modes[];
 
-extern MeterClass BlankMeter_class;
+extern const MeterClass BlankMeter_class;
 
 #endif
diff --git a/MetersPanel.c b/MetersPanel.c
index 6f59f013..36cc8f45 100644
--- a/MetersPanel.c
+++ b/MetersPanel.c
@@ -186,7 +186,7 @@ static HandlerResult MetersPanel_eventHandler(Panel* super, int ch) {
    return result;
 }
 
-PanelClass MetersPanel_class = {
+const PanelClass MetersPanel_class = {
    .super = {
       .extends = Class(Panel),
       .delete = MetersPanel_delete
diff --git a/MetersPanel.h b/MetersPanel.h
index 50148944..760388d8 100644
--- a/MetersPanel.h
+++ b/MetersPanel.h
@@ -28,7 +28,7 @@ void MetersPanel_cleanup(void);
 
 void MetersPanel_setMoving(MetersPanel* this, bool moving);
 
-extern PanelClass MetersPanel_class;
+extern const PanelClass MetersPanel_class;
 
 MetersPanel* MetersPanel_new(Settings* settings, const char* header, Vector* meters, ScreenManager* scr);
 
diff --git a/OpenFilesScreen.c b/OpenFilesScreen.c
index 652e0748..7c0acebe 100644
--- a/OpenFilesScreen.c
+++ b/OpenFilesScreen.c
@@ -24,7 +24,7 @@ in the source distribution for its full text.
 #include <sys/wait.h>
 
 
-InfoScreenClass OpenFilesScreen_class = {
+const InfoScreenClass OpenFilesScreen_class = {
    .super = {
       .extends = Class(Object),
       .delete = OpenFilesScreen_delete
diff --git a/OpenFilesScreen.h b/OpenFilesScreen.h
index 9d63fe7a..9a12dcd0 100644
--- a/OpenFilesScreen.h
+++ b/OpenFilesScreen.h
@@ -29,7 +29,7 @@ typedef struct OpenFilesScreen_ {
    pid_t pid;
 } OpenFilesScreen;
 
-extern InfoScreenClass OpenFilesScreen_class;
+extern const InfoScreenClass OpenFilesScreen_class;
 
 OpenFilesScreen* OpenFilesScreen_new(Process* process);
 
diff --git a/Panel.c b/Panel.c
index 5922d4c7..06a15c6b 100644
--- a/Panel.c
+++ b/Panel.c
@@ -19,7 +19,7 @@ in the source distribution for its full text.
 #include <string.h>
 #include <assert.h>
 
-PanelClass Panel_class = {
+const PanelClass Panel_class = {
    .super = {
       .extends = Class(Object),
       .delete = Panel_delete
diff --git a/Panel.h b/Panel.h
index 7c4a6f2f..4b28c42d 100644
--- a/Panel.h
+++ b/Panel.h
@@ -60,7 +60,7 @@ struct Panel_ {
 
 #define KEY_CTRL(l) ((l)-'A'+1)
 
-extern PanelClass Panel_class;
+extern const PanelClass Panel_class;
 
 Panel* Panel_new(int x, int y, int w, int h, bool owner, const ObjectClass* type, FunctionBar* fuBar);
 
diff --git a/Process.c b/Process.c
index 07ea1382..ea703e4b 100644
--- a/Process.c
+++ b/Process.c
@@ -384,7 +384,7 @@ void Process_done(Process* this) {
    free(this->comm);
 }
 
-ProcessClass Process_class = {
+const ProcessClass Process_class = {
    .super = {
       .extends = Class(Object),
       .display = Process_display,
diff --git a/Process.h b/Process.h
index 2ff7f5e0..beca4f25 100644
--- a/Process.h
+++ b/Process.h
@@ -162,7 +162,7 @@ void Process_display(Object* cast, RichString* out);
 
 void Process_done(Process* this);
 
-extern ProcessClass Process_class;
+extern const ProcessClass Process_class;
 
 void Process_init(Process* this, struct Settings_* settings);
 
diff --git a/SwapMeter.c b/SwapMeter.c
index 93a34e8f..e754bbe6 100644
--- a/SwapMeter.c
+++ b/SwapMeter.c
@@ -45,7 +45,7 @@ static void SwapMeter_display(Object* cast, RichString* out) {
    RichString_append(out, CRT_colors[METER_VALUE], buffer);
 }
 
-MeterClass SwapMeter_class = {
+const MeterClass SwapMeter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete,
diff --git a/SwapMeter.h b/SwapMeter.h
index 502e6ee6..623a0364 100644
--- a/SwapMeter.h
+++ b/SwapMeter.h
@@ -9,6 +9,6 @@ in the source distribution for its full text.
 
 #include "Meter.h"
 
-extern MeterClass SwapMeter_class;
+extern const MeterClass SwapMeter_class;
 
 #endif
diff --git a/TasksMeter.c b/TasksMeter.c
index eb727cc2..bf289e99 100644
--- a/TasksMeter.c
+++ b/TasksMeter.c
@@ -66,7 +66,7 @@ static void TasksMeter_display(Object* cast, RichString* out) {
    RichString_append(out, CRT_colors[METER_TEXT], " running");
 }
 
-MeterClass TasksMeter_class = {
+const MeterClass TasksMeter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete,
diff --git a/TasksMeter.h b/TasksMeter.h
index 8be826be..cecb4013 100644
--- a/TasksMeter.h
+++ b/TasksMeter.h
@@ -9,6 +9,6 @@ in the source distribution for its full text.
 
 #include "Meter.h"
 
-extern MeterClass TasksMeter_class;
+extern const MeterClass TasksMeter_class;
 
 #endif
diff --git a/TraceScreen.c b/TraceScreen.c
index 18406454..8e5f61e7 100644
--- a/TraceScreen.c
+++ b/TraceScreen.c
@@ -33,7 +33,7 @@ static const char* const TraceScreenKeys[] = {"F3", "F4", "F8", "F9", "Esc"};
 
 static int TraceScreenEvents[] = {KEY_F(3), KEY_F(4), KEY_F(8), KEY_F(9), 27};
 
-InfoScreenClass TraceScreen_class = {
+const InfoScreenClass TraceScreen_class = {
    .super = {
       .extends = Class(Object),
       .delete = TraceScreen_delete
diff --git a/TraceScreen.h b/TraceScreen.h
index 04b0848f..513ea461 100644
--- a/TraceScreen.h
+++ b/TraceScreen.h
@@ -21,7 +21,7 @@ typedef struct TraceScreen_ {
 } TraceScreen;
 
 
-extern InfoScreenClass TraceScreen_class;
+extern const InfoScreenClass TraceScreen_class;
 
 TraceScreen* TraceScreen_new(Process* process);
 
diff --git a/UptimeMeter.c b/UptimeMeter.c
index 07c4169b..a1195186 100644
--- a/UptimeMeter.c
+++ b/UptimeMeter.c
@@ -41,7 +41,7 @@ static void UptimeMeter_updateValues(Meter* this, char* buffer, int len) {
    xSnprintf(buffer, len, "%s%02d:%02d:%02d", daysbuf, hours, minutes, seconds);
 }
 
-MeterClass UptimeMeter_class = {
+const MeterClass UptimeMeter_class = {
    .super = {
       .extends = Class(Meter),
       .delete = Meter_delete
diff --git a/UptimeMeter.h b/UptimeMeter.h
index aef3ac37..49300bbb 100644
--- a/UptimeMeter.h
+++ b/UptimeMeter.h
@@ -9,6 +9,6 @@ in the source distribution for its full text.
 
 #include "Meter.h"
 
-extern MeterClass UptimeMeter_class;
+extern const MeterClass UptimeMeter_class;
 
 #endif
diff --git a/darwin/Platform.c b/darwin/Platform.c
index fabf5520..4d8ede32 100644
--- a/darwin/Platform.c
+++ b/darwin/Platform.c
@@ -94,7 +94,7 @@ ProcessFieldData Process_fields[] = {
    [100] = { .name = "*** report bug! ***", .title = NULL, .description = NULL, .flags = 0, },
 };
 
-MeterClass* Platform_meterTypes[] = {
+const MeterClass* const Platform_meterTypes[] = {
    &CPUMeter_class,
    &ClockMeter_class,
    &DateMeter_class,
diff --git a/darwin/Platform.h b/darwin/Platform.h
index ba779976..9b7a324b 100644
--- a/darwin/Platform.h
+++ b/darwin/Platform.h
@@ -22,7 +22,7 @@ extern const unsigned int Platform_numberOfSignals;
 
 extern ProcessFieldData Process_fields[];
 
-extern MeterClass* Platform_meterTypes[];
+extern const MeterClass* const Platform_meterTypes[];
 
 void Platform_setBindings(Htop_Action* keys);
 
diff --git a/dragonflybsd/Platform.c b/dragonflybsd/Platform.c
index 33282405..21ebc40a 100644
--- a/dragonflybsd/Platform.c
+++ b/dragonflybsd/Platform.c
@@ -77,7 +77,7 @@ void Platform_setBindings(Htop_Action* keys) {
    (void) keys;
 }
 
-MeterClass* Platform_meterTypes[] = {
+const MeterClass* const Platform_meterTypes[] = {
    &CPUMeter_class,
    &ClockMeter_class,
    &DateMeter_class,
diff --git a/dragonflybsd/Platform.h b/dragonflybsd/Platform.h
index 5dfd28c0..3dc1eb1e 100644
--- a/dragonflybsd/Platform.h
+++ b/dragonflybsd/Platform.h
@@ -24,7 +24,7 @@ extern const unsigned int Platform_numberOfSignals;
 
 void Platform_setBindings(Htop_Action* keys);
 
-extern MeterClass* Platform_meterTypes[];
+extern const MeterClass* const Platform_meterTypes[];
 
 int Platform_getUptime(void);
 
diff --git a/freebsd/Platform.c b/freebsd/Platform.c
index 3e4b9b74..9c91de15 100644
--- a/freebsd/Platform.c
+++ b/freebsd/Platform.c
@@ -78,7 +78,7 @@ void Platform_setBindings(Htop_Action* keys) {
    (void) keys;
 }
 
-MeterClass* Platform_meterTypes[] = {
+const MeterClass* const Platform_meterTypes[] = {
    &CPUMeter_class,
    &ClockMeter_class,
    &DateMeter_class,
diff --git a/freebsd/Platform.h b/freebsd/Platform.h
index 09783afc..feda7416 100644
--- a/freebsd/Platform.h
+++ b/freebsd/Platform.h
@@ -23,7 +23,7 @@ extern const unsigned int Platform_numberOfSignals;
 
 void Platform_setBindings(Htop_Action* keys);
 
-extern MeterClass* Platform_meterTypes[];
+extern const MeterClass* const Platform_meterTypes[];
 
 int Platform_getUptime(void);
 
diff --git a/linux/Platform.c b/linux/Platform.c
index 6ec0d076..e0a03548 100644
--- a/linux/Platform.c
+++ b/linux/Platform.c
@@ -105,7 +105,7 @@ void Platform_setBindings(Htop_Action* keys) {
    keys['i'] = Platform_actionSetIOPriority;
 }
 
-MeterClass* Platform_meterTypes[] = {
+const MeterClass* const Platform_meterTypes[] = {
    &CPUMeter_class,
    &ClockMeter_class,
    &DateMeter_class,
diff --git a/linux/Platform.h b/linux/Platform.h
index 58f5acec..66a60d8b 100644
--- a/linux/Platform.h
+++ b/linux/Platform.h
@@ -23,7 +23,7 @@ extern const unsigned int Platform_numberOfSignals;
 
 void Platform_setBindings(Htop_Action* keys);
 
-extern MeterClass* Platform_meterTypes[];
+extern const MeterClass* const Platform_meterTypes[];
 
 int Platform_getUptime(void);
 
diff --git a/openbsd/Platform.c b/openbsd/Platform.c
index 0368d722..02a821e7 100644
--- a/openbsd/Platform.c
+++ b/openbsd/Platform.c
@@ -90,7 +90,7 @@ void Platform_setBindings(Htop_Action* keys) {
    (void) keys;
 }
 
-MeterClass* Platform_meterTypes[] = {
+const MeterClass* const Platform_meterTypes[] = {
    &CPUMeter_class,
    &ClockMeter_class,
    &DateMeter_class,
diff --git a/openbsd/Platform.h b/openbsd/Platform.h
index dc9b0fa3..c71d490e 100644
--- a/openbsd/Platform.h
+++ b/openbsd/Platform.h
@@ -25,7 +25,7 @@ extern const unsigned int Platform_numberOfSignals;
 
 void Platform_setBindings(Htop_Action* keys);
 
-extern MeterClass* Platform_meterTypes[];
+extern const MeterClass* const Platform_meterTypes[];
 
 int Platform_getUptime(void);
 
diff --git a/solaris/Platform.c b/solaris/Platform.c
index 5f737342..e1243bfa 100644
--- a/solaris/Platform.c
+++ b/solaris/Platform.c
@@ -87,7 +87,7 @@ const unsigned int Platform_numberOfSignals = sizeof(Platform_signals)/sizeof(Si
 
 ProcessField Platform_defaultFields[] = { PID, LWPID, USER, PRIORITY, NICE, M_SIZE, M_RESIDENT, STATE, PERCENT_CPU, PERCENT_MEM, TIME, COMM, 0 };
 
-MeterClass* Platform_meterTypes[] = {
+const MeterClass* const Platform_meterTypes[] = {
    &CPUMeter_class,
    &ClockMeter_class,
    &DateMeter_class,
diff --git a/solaris/Platform.h b/solaris/Platform.h
index fa8be103..a9b7712d 100644
--- a/solaris/Platform.h
+++ b/solaris/Platform.h
@@ -37,7 +37,7 @@ extern const unsigned int Platform_numberOfSignals;
 
 extern ProcessField Platform_defaultFields[];
 
-extern MeterClass* Platform_meterTypes[];
+extern const MeterClass* const Platform_meterTypes[];
 
 void Platform_setBindings(Htop_Action* keys);
 
diff --git a/unsupported/Platform.c b/unsupported/Platform.c
index da360a31..304989ee 100644
--- a/unsupported/Platform.c
+++ b/unsupported/Platform.c
@@ -58,7 +58,7 @@ ProcessFieldData Process_fields[] = {
    [100] = { .name = "*** report bug! ***", .title = NULL, .description = NULL, .flags = 0, },
 };
 
-MeterClass* Platform_meterTypes[] = {
+const MeterClass* const Platform_meterTypes[] = {
    &CPUMeter_class,
    &ClockMeter_class,
    &DateMeter_class,
diff --git a/unsupported/Platform.h b/unsupported/Platform.h
index 8349d97a..ce188afa 100644
--- a/unsupported/Platform.h
+++ b/unsupported/Platform.h
@@ -21,7 +21,7 @@ extern ProcessField Platform_defaultFields[];
 
 extern ProcessFieldData Process_fields[];
 
-extern MeterClass* Platform_meterTypes[];
+extern const MeterClass* const Platform_meterTypes[];
 
 void Platform_setBindings(Htop_Action* keys);