Mark several non-modified pointer variables const

33 files changed, 97 insertions, 100 deletions

diff --git a/Action.c b/Action.c
index 88ccf6df..578882db 100644
--- a/Action.c
+++ b/Action.c
@@ -43,10 +43,9 @@ in the source distribution for its full text.
 Object* Action_pickFromVector(State* st, Panel* list, int x, bool followProcess) {
    Panel* panel = st->panel;
    Header* header = st->header;
-   Settings* settings = st->settings;
 
    int y = panel->y;
-   ScreenManager* scr = ScreenManager_new(header, settings, st, false);
+   ScreenManager* scr = ScreenManager_new(header, st->settings, st, false);
    scr->allowFocusChange = false;
    ScreenManager_add(scr, list, x - 1);
    ScreenManager_add(scr, panel, -1);
@@ -67,7 +66,7 @@ Object* Action_pickFromVector(State* st, Panel* list, int x, bool followProcess)
    Panel_resize(panel, COLS, LINES - y - 1);
    if (panelFocus == list && ch == 13) {
       if (followProcess) {
-         Process* selected = (Process*)Panel_getSelected(panel);
+         const Process* selected = (const Process*)Panel_getSelected(panel);
          if (selected && selected->pid == pid)
             return Panel_getSelected(list);
 
@@ -141,7 +140,7 @@ static bool expandCollapse(Panel* panel) {
 }
 
 static bool collapseIntoParent(Panel* panel) {
-   Process* p = (Process*) Panel_getSelected(panel);
+   const Process* p = (Process*) Panel_getSelected(panel);
    if (!p)
       return false;
 
@@ -168,7 +167,7 @@ static Htop_Reaction actionSetSortColumn(State* st) {
    Htop_Reaction reaction = HTOP_OK;
    Panel* sortPanel = Panel_new(0, 0, 0, 0, Class(ListItem), true, FunctionBar_newEnterEsc("Sort   ", "Cancel "));
    Panel_setHeader(sortPanel, "Sort by");
-   ProcessField* fields = st->settings->fields;
+   const ProcessField* fields = st->settings->fields;
    for (int i = 0; fields[i]; i++) {
       char* name = String_trim(Process_fields[fields[i]].name);
       Panel_add(sortPanel, (Object*) ListItem_new(name, fields[i]));
@@ -177,7 +176,7 @@ static Htop_Reaction actionSetSortColumn(State* st) {
 
       free(name);
    }
-   ListItem* field = (ListItem*) Action_pickFromVector(st, sortPanel, 15, false);
+   const ListItem* field = (const ListItem*) Action_pickFromVector(st, sortPanel, 15, false);
    if (field) {
       reaction |= Action_setSortKey(st->settings, field->key);
    }
@@ -293,7 +292,7 @@ static Htop_Reaction actionSetAffinity(State* st) {
 #if (defined(HAVE_LIBHWLOC) || defined(HAVE_LINUX_AFFINITY))
    Panel* panel = st->panel;
 
-   Process* p = (Process*) Panel_getSelected(panel);
+   const Process* p = (const Process*) Panel_getSelected(panel);
    if (!p)
       return HTOP_OK;
 
@@ -306,7 +305,7 @@ static Htop_Reaction actionSetAffinity(State* st) {
    width += 1; /* we add a gap between the panels */
    Affinity_delete(affinity1);
 
-   void* set = Action_pickFromVector(st, affinityPanel, width, true);
+   const void* set = Action_pickFromVector(st, affinityPanel, width, true);
    if (set) {
       Affinity* affinity2 = AffinityPanel_getAffinity(affinityPanel, st->pl);
       bool ok = MainPanel_foreachProcess((MainPanel*)panel, Affinity_set, (Arg) { .v = affinity2 }, NULL);
@@ -321,7 +320,7 @@ static Htop_Reaction actionSetAffinity(State* st) {
 
 static Htop_Reaction actionKill(State* st) {
    Panel* signalsPanel = SignalsPanel_new();
-   ListItem* sgn = (ListItem*) Action_pickFromVector(st, signalsPanel, 15, true);
+   const ListItem* sgn = (ListItem*) Action_pickFromVector(st, signalsPanel, 15, true);
    if (sgn) {
       if (sgn->key != 0) {
          Panel_setHeader(st->panel, "Sending...");
@@ -342,7 +341,7 @@ static Htop_Reaction actionFilterByUser(State* st) {
    Vector_insertionSort(usersPanel->items);
    ListItem* allUsers = ListItem_new("All users", -1);
    Panel_insert(usersPanel, 0, (Object*) allUsers);
-   ListItem* picked = (ListItem*) Action_pickFromVector(st, usersPanel, 20, false);
+   const ListItem* picked = (ListItem*) Action_pickFromVector(st, usersPanel, 20, false);
    if (picked) {
       if (picked == allUsers) {
          st->pl->userId = (uid_t)-1;
@@ -370,7 +369,7 @@ static Htop_Reaction actionSetup(State* st) {
 }
 
 static Htop_Reaction actionLsof(State* st) {
-   Process* p = (Process*) Panel_getSelected(st->panel);
+   const Process* p = (Process*) Panel_getSelected(st->panel);
    if (!p)
       return HTOP_OK;
 
@@ -383,7 +382,7 @@ static Htop_Reaction actionLsof(State* st) {
 }
 
 static Htop_Reaction actionShowLocks(State* st) {
-   Process* p = (Process*) Panel_getSelected(st->panel);
+   const Process* p = (Process*) Panel_getSelected(st->panel);
    if (!p) return HTOP_OK;
    ProcessLocksScreen* pls = ProcessLocksScreen_new(p);
    InfoScreen_run((InfoScreen*)pls);
@@ -394,7 +393,7 @@ static Htop_Reaction actionShowLocks(State* st) {
 }
 
 static Htop_Reaction actionStrace(State* st) {
-   Process* p = (Process*) Panel_getSelected(st->panel);
+   const Process* p = (Process*) Panel_getSelected(st->panel);
    if (!p)
       return HTOP_OK;
 
@@ -483,8 +482,6 @@ static inline void addattrstr( int attr, const char* str) {
 }
 
 static Htop_Reaction actionHelp(State* st) {
-   Settings* settings = st->settings;
-
    clear();
    attrset(CRT_colors[HELP_BOLD]);
 
@@ -501,7 +498,7 @@ static Htop_Reaction actionHelp(State* st) {
    mvaddstr(line++, 0, "CPU usage bar: ");
 
    addattrstr(CRT_colors[BAR_BORDER], "[");
-   if (settings->detailedCPUTime) {
+   if (st->settings->detailedCPUTime) {
       addattrstr(CRT_colors[CPU_NICE_TEXT], "low"); addstr("/");
       addattrstr(CRT_colors[CPU_NORMAL], "normal"); addstr("/");
       addattrstr(CRT_colors[CPU_SYSTEM], "kernel"); addstr("/");
diff --git a/Affinity.c b/Affinity.c
index c157885b..6b39b399 100644
--- a/Affinity.c
+++ b/Affinity.c
@@ -52,7 +52,7 @@ void Affinity_add(Affinity* this, int id) {
 
 #ifdef HAVE_LIBHWLOC
 
-Affinity* Affinity_get(Process* proc, ProcessList* pl) {
+Affinity* Affinity_get(const Process* proc, ProcessList* pl) {
    hwloc_cpuset_t cpuset = hwloc_bitmap_alloc();
    bool ok = (hwloc_get_proc_cpubind(pl->topology, proc->pid, cpuset, HTOP_HWLOC_CPUBIND_FLAG) == 0);
    Affinity* affinity = NULL;
@@ -86,7 +86,7 @@ bool Affinity_set(Process* proc, Arg arg) {
 
 #elif defined(HAVE_LINUX_AFFINITY)
 
-Affinity* Affinity_get(Process* proc, ProcessList* pl) {
+Affinity* Affinity_get(const Process* proc, ProcessList* pl) {
    cpu_set_t cpuset;
    bool ok = (sched_getaffinity(proc->pid, sizeof(cpu_set_t), &cpuset) == 0);
    if (!ok)
diff --git a/Affinity.h b/Affinity.h
index 97c8e466..980b15b5 100644
--- a/Affinity.h
+++ b/Affinity.h
@@ -40,7 +40,7 @@ void Affinity_add(Affinity* this, int id);
 
 #if defined(HAVE_LIBHWLOC) || defined(HAVE_LINUX_AFFINITY)
 
-Affinity* Affinity_get(Process* proc, ProcessList* pl);
+Affinity* Affinity_get(const Process* proc, ProcessList* pl);
 
 bool Affinity_set(Process* proc, Arg arg);
 
diff --git a/AffinityPanel.c b/AffinityPanel.c
index a4d63616..57211050 100644
--- a/AffinityPanel.c
+++ b/AffinityPanel.c
@@ -357,7 +357,7 @@ static const char* const AffinityPanelFunctions[] = {
 static const char* const AffinityPanelKeys[] = {"Enter", "Esc", "F1", "F2", "F3"};
 static const int AffinityPanelEvents[] = {13, 27, KEY_F(1), KEY_F(2), KEY_F(3)};
 
-Panel* AffinityPanel_new(ProcessList* pl, Affinity* affinity, int* width) {
+Panel* AffinityPanel_new(ProcessList* pl, const Affinity* affinity, int* width) {
    AffinityPanel* this = AllocThis(AffinityPanel);
    Panel* super = (Panel*) this;
    Panel_init(super, 1, 1, 1, 1, Class(MaskItem), false, FunctionBar_new(AffinityPanelFunctions, AffinityPanelKeys, AffinityPanelEvents));
@@ -418,7 +418,7 @@ Panel* AffinityPanel_new(ProcessList* pl, Affinity* affinity, int* width) {
 }
 
 Affinity* AffinityPanel_getAffinity(Panel* super, ProcessList* pl) {
-   AffinityPanel* this = (AffinityPanel*) super;
+   const AffinityPanel* this = (AffinityPanel*) super;
    Affinity* affinity = Affinity_new(pl);
 
    #ifdef HAVE_LIBHWLOC
@@ -428,7 +428,7 @@ Affinity* AffinityPanel_getAffinity(Panel* super, ProcessList* pl) {
    hwloc_bitmap_foreach_end();
    #else
    for (int i = 0; i < this->pl->cpuCount; i++) {
-      MaskItem* item = (MaskItem*)Vector_get(this->cpuids, i);
+      const MaskItem* item = (const MaskItem*)Vector_get(this->cpuids, i);
       if (item->value) {
          Affinity_add(affinity, item->cpu);
       }
diff --git a/AffinityPanel.h b/AffinityPanel.h
index fdefeae4..e95c7325 100644
--- a/AffinityPanel.h
+++ b/AffinityPanel.h
@@ -13,7 +13,7 @@ in the source distribution for its full text.
 
 extern const PanelClass AffinityPanel_class;
 
-Panel* AffinityPanel_new(ProcessList* pl, Affinity* affinity, int* width);
+Panel* AffinityPanel_new(ProcessList* pl, const Affinity* affinity, int* width);
 
 Affinity* AffinityPanel_getAffinity(Panel* super, ProcessList* pl);
 
diff --git a/AvailableMetersPanel.c b/AvailableMetersPanel.c
index 7c82229b..fd3a9cb6 100644
--- a/AvailableMetersPanel.c
+++ b/AvailableMetersPanel.c
@@ -90,7 +90,7 @@ const PanelClass AvailableMetersPanel_class = {
    .eventHandler = AvailableMetersPanel_eventHandler
 };
 
-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, const ProcessList* pl) {
    AvailableMetersPanel* this = AllocThis(AvailableMetersPanel);
    Panel* super = (Panel*) this;
    FunctionBar* fuBar = FunctionBar_newEnterEsc("Add   ", "Done   ");
diff --git a/AvailableMetersPanel.h b/AvailableMetersPanel.h
index f7359365..a9c0da95 100644
--- a/AvailableMetersPanel.h
+++ b/AvailableMetersPanel.h
@@ -25,6 +25,6 @@ typedef struct AvailableMetersPanel_ {
 
 extern const PanelClass AvailableMetersPanel_class;
 
-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, const ProcessList* pl);
 
 #endif
diff --git a/CPUMeter.c b/CPUMeter.c
index d84e4db7..a39a3cb9 100644
--- a/CPUMeter.c
+++ b/CPUMeter.c
@@ -167,8 +167,8 @@ static void CPUMeter_display(const Object* cast, RichString* out) {
    #endif
 }
 
-static void AllCPUsMeter_getRange(Meter* this, int* start, int* count) {
-   CPUMeterData* data = this->meterData;
+static void AllCPUsMeter_getRange(const Meter* this, int* start, int* count) {
+   const CPUMeterData* data = this->meterData;
    int cpus = data->cpus;
    switch(Meter_name(this)[0]) {
       default:
diff --git a/ClockMeter.c b/ClockMeter.c
index 023ca425..654d9074 100644
--- a/ClockMeter.c
+++ b/ClockMeter.c
@@ -22,7 +22,7 @@ static const int ClockMeter_attributes[] = {
 static void ClockMeter_updateValues(Meter* this, char* buffer, size_t size) {
    time_t t = time(NULL);
    struct tm result;
-   struct tm* lt = localtime_r(&t, &result);
+   const struct tm* lt = localtime_r(&t, &result);
    this->values[0] = lt->tm_hour * 60 + lt->tm_min;
    strftime(buffer, size, "%H:%M:%S", lt);
 }
diff --git a/ColumnsPanel.c b/ColumnsPanel.c
index ea561663..5382db0b 100644
--- a/ColumnsPanel.c
+++ b/ColumnsPanel.c
@@ -125,7 +125,7 @@ ColumnsPanel* ColumnsPanel_new(Settings* settings) {
    this->moving = false;
    Panel_setHeader(super, "Active Columns");
 
-   ProcessField* fields = this->settings->fields;
+   const ProcessField* fields = this->settings->fields;
    for (; *fields; fields++) {
       if (Process_fields[*fields].name) {
          Panel_add(super, (Object*) ListItem_new(Process_fields[*fields].name, *fields));
diff --git a/DateMeter.c b/DateMeter.c
index bd6a306b..44f2ec0b 100644
--- a/DateMeter.c
+++ b/DateMeter.c
@@ -22,7 +22,7 @@ static const int DateMeter_attributes[] = {
 static void DateMeter_updateValues(Meter* this, char* buffer, size_t size) {
    time_t t = time(NULL);
    struct tm result;
-   struct tm* lt = localtime_r(&t, &result);
+   const struct tm* lt = localtime_r(&t, &result);
    this->values[0] = lt->tm_yday;
    int year = lt->tm_year + 1900;
    if (((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0)) {
diff --git a/DateTimeMeter.c b/DateTimeMeter.c
index 0d231cd5..29886751 100644
--- a/DateTimeMeter.c
+++ b/DateTimeMeter.c
@@ -22,7 +22,7 @@ static const int DateTimeMeter_attributes[] = {
 static void DateTimeMeter_updateValues(Meter* this, char* buffer, size_t size) {
    time_t t = time(NULL);
    struct tm result;
-   struct tm* lt = localtime_r(&t, &result);
+   const struct tm* lt = localtime_r(&t, &result);
    int year = lt->tm_year + 1900;
    if (((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0)) {
       this->total = 366;
diff --git a/EnvScreen.c b/EnvScreen.c
index acd1f330..4d7de7d9 100644
--- a/EnvScreen.c
+++ b/EnvScreen.c
@@ -38,7 +38,7 @@ static void EnvScreen_scan(InfoScreen* this) {
    char* env = Platform_getProcessEnv(this->process->pid);
    CRT_restorePrivileges();
    if (env) {
-      for (char* p = env; *p; p = strrchr(p, 0) + 1)
+      for (const char* p = env; *p; p = strrchr(p, 0) + 1)
          InfoScreen_addLine(this, p);
       free(env);
    }
diff --git a/Header.c b/Header.c
index 24c40771..292f9b1e 100644
--- a/Header.c
+++ b/Header.c
@@ -42,7 +42,7 @@ void Header_delete(Header* this) {
 
 void Header_populateFromSettings(Header* this) {
    Header_forEachColumn(this, col) {
-      MeterColumnSettings* colSettings = &this->settings->columns[col];
+      const MeterColumnSettings* colSettings = &this->settings->columns[col];
       for (int i = 0; i < colSettings->len; i++) {
          Header_addMeterByName(this, colSettings->names[i], col);
          if (colSettings->modes[i] != 0) {
@@ -60,7 +60,7 @@ void Header_writeBackToSettings(const Header* this) {
       String_freeArray(colSettings->names);
       free(colSettings->modes);
 
-      Vector* vec = this->columns[col];
+      const Vector* vec = this->columns[col];
       int len = Vector_size(vec);
 
       colSettings->names = xCalloc(len + 1, sizeof(char*));
@@ -68,7 +68,7 @@ void Header_writeBackToSettings(const Header* this) {
       colSettings->len = len;
 
       for (int i = 0; i < len; i++) {
-         Meter* meter = (Meter*) Vector_get(vec, i);
+         const Meter* meter = (Meter*) Vector_get(vec, i);
          char* name;
          if (meter->param) {
             xAsprintf(&name, "%s(%d)", As_Meter(meter)->name, meter->param);
@@ -81,7 +81,7 @@ void Header_writeBackToSettings(const Header* this) {
    }
 }
 
-MeterModeId Header_addMeterByName(Header* this, char* name, int column) {
+MeterModeId Header_addMeterByName(Header* this, const char* name, int column) {
    Vector* meters = this->columns[column];
 
    char* paren = strchr(name, '(');
@@ -126,15 +126,15 @@ Meter* Header_addMeterByClass(Header* this, const MeterClass* type, int param, i
    return meter;
 }
 
-int Header_size(Header* this, int column) {
-   Vector* meters = this->columns[column];
+int Header_size(const Header* this, int column) {
+   const Vector* meters = this->columns[column];
    return Vector_size(meters);
 }
 
-MeterModeId Header_readMeterMode(Header* this, int i, int column) {
-   Vector* meters = this->columns[column];
+MeterModeId Header_readMeterMode(const Header* this, int i, int column) {
+   const Vector* meters = this->columns[column];
 
-   Meter* meter = (Meter*) Vector_get(meters, i);
+   const Meter* meter = (const Meter*) Vector_get(meters, i);
    return meter->mode;
 }
 
@@ -175,10 +175,10 @@ int Header_calculateHeight(Header* this) {
    int maxHeight = pad;
 
    Header_forEachColumn(this, col) {
-      Vector* meters = this->columns[col];
+      const Vector* meters = this->columns[col];
       int height = pad;
       for (int i = 0; i < Vector_size(meters); i++) {
-         Meter* meter = (Meter*) Vector_get(meters, i);
+         const Meter* meter = (const Meter*) Vector_get(meters, i);
          height += meter->h;
       }
       maxHeight = MAXIMUM(maxHeight, height);
diff --git a/Header.h b/Header.h
index 870fbd85..11283c74 100644
--- a/Header.h
+++ b/Header.h
@@ -31,15 +31,15 @@ void Header_populateFromSettings(Header* this);
 
 void Header_writeBackToSettings(const Header* this);
 
-MeterModeId Header_addMeterByName(Header* this, char* name, int column);
+MeterModeId Header_addMeterByName(Header* this, const char* name, int column);
 
 void Header_setMode(Header* this, int i, MeterModeId mode, int column);
 
 Meter* Header_addMeterByClass(Header* this, const MeterClass* type, int param, int column);
 
-int Header_size(Header* this, int column);
+int Header_size(const Header* this, int column);
 
-MeterModeId Header_readMeterMode(Header* this, int i, int column);
+MeterModeId Header_readMeterMode(const Header* this, int i, int column);
 
 void Header_reinit(Header* this);
 
diff --git a/IncSet.c b/IncSet.c
index f1031bd0..90974137 100644
--- a/IncSet.c
+++ b/IncSet.c
@@ -77,8 +77,8 @@ void IncSet_delete(IncSet* this) {
    free(this);
 }
 
-static void updateWeakPanel(IncSet* this, Panel* panel, Vector* lines) {
-   Object* selected = Panel_getSelected(panel);
+static void updateWeakPanel(const IncSet* this, Panel* panel, Vector* lines) {
+   const Object* selected = Panel_getSelected(panel);
    Panel_prune(panel);
    if (this->filtering) {
       int n = 0;
@@ -105,7 +105,7 @@ static void updateWeakPanel(IncSet* this, Panel* panel, Vector* lines) {
    }
 }
 
-static bool search(IncMode* mode, Panel* panel, IncMode_GetPanelValue getPanelValue) {
+static bool search(const IncMode* mode, Panel* panel, IncMode_GetPanelValue getPanelValue) {
    int size = Panel_size(panel);
    for (int i = 0; i < size; i++) {
       if (String_contains_i(getPanelValue(panel, i), mode->buffer)) {
@@ -117,7 +117,7 @@ static bool search(IncMode* mode, Panel* panel, IncMode_GetPanelValue getPanelVa
    return false;
 }
 
-static bool IncMode_find(IncMode* mode, Panel* panel, IncMode_GetPanelValue getPanelValue, int step) {
+static bool IncMode_find(const IncMode* mode, Panel* panel, IncMode_GetPanelValue getPanelValue, int step) {
    int size = Panel_size(panel);
    int here = Panel_getSelectedIndex(panel);
    int i = here;
@@ -208,7 +208,7 @@ bool IncSet_handleKey(IncSet* this, int ch, Panel* panel, IncMode_GetPanelValue
 }
 
 const char* IncSet_getListItemValue(Panel* panel, int i) {
-   ListItem* l = (ListItem*) Panel_get(panel, i);
+   const ListItem* l = (const ListItem*) Panel_get(panel, i);
    return l ? l->value : "";
 }
 
diff --git a/MainPanel.c b/MainPanel.c
index 859c5130..842e8e15 100644
--- a/MainPanel.c
+++ b/MainPanel.c
@@ -32,7 +32,7 @@ void MainPanel_pidSearch(MainPanel* this, int ch) {
    Panel* super = (Panel*) this;
    pid_t pid = ch - 48 + this->pidSearch;
    for (int i = 0; i < Panel_size(super); i++) {
-      Process* p = (Process*) Panel_get(super, i);
+      const Process* p = (const Process*) Panel_get(super, i);
       if (p && p->pid == pid) {
          Panel_setSelected(super, i);
          break;
@@ -134,7 +134,7 @@ static HandlerResult MainPanel_eventHandler(Panel* super, int ch) {
 }
 
 int MainPanel_selectedPid(MainPanel* this) {
-   Process* p = (Process*) Panel_getSelected((Panel*)this);
+   const Process* p = (const Process*) Panel_getSelected((Panel*)this);
    if (p) {
       return p->pid;
    }
diff --git a/Meter.c b/Meter.c
index ed9571df..5189c87a 100644
--- a/Meter.c
+++ b/Meter.c
@@ -131,7 +131,7 @@ void Meter_setMode(Meter* this, int modeIndex) {
    this->mode = modeIndex;
 }
 
-ListItem* Meter_toListItem(Meter* this, bool moving) {
+ListItem* Meter_toListItem(const Meter* this, bool moving) {
    char mode[20];
    if (this->mode) {
       xSnprintf(mode, sizeof(mode), " [%s]", Meter_modes[this->mode]->uiName);
diff --git a/Meter.h b/Meter.h
index 2a78fd10..98fed575 100644
--- a/Meter.h
+++ b/Meter.h
@@ -133,7 +133,7 @@ void Meter_setCaption(Meter* this, const char* caption);
 
 void Meter_setMode(Meter* this, int modeIndex);
 
-ListItem* Meter_toListItem(Meter* this, bool moving);
+ListItem* Meter_toListItem(const Meter* this, bool moving);
 
 extern const MeterMode* const Meter_modes[];
 
diff --git a/Panel.c b/Panel.c
index 5d103753..986a9895 100644
--- a/Panel.c
+++ b/Panel.c
@@ -172,13 +172,13 @@ void Panel_moveSelectedDown(Panel* this) {
    }
 }
 
-int Panel_getSelectedIndex(Panel* this) {
+int Panel_getSelectedIndex(const Panel* this) {
    assert (this != NULL);
 
    return this->selected;
 }
 
-int Panel_size(Panel* this) {
+int Panel_size(const Panel* this) {
    assert (this != NULL);
 
    return Vector_size(this->items);
@@ -269,7 +269,7 @@ void Panel_draw(Panel* this, bool force_redraw, bool focus, bool highlightSelect
    if (this->needsRedraw || force_redraw) {
       int line = 0;
       for (int i = first; line < h && i < upTo; i++) {
-         Object* itemObj = Vector_get(this->items, i);
+         const Object* itemObj = Vector_get(this->items, i);
          RichString_begin(item);
          Object_display(itemObj, &item);
          int itemLen = RichString_sizeVal(item);
@@ -296,11 +296,11 @@ void Panel_draw(Panel* this, bool force_redraw, bool focus, bool highlightSelect
       }
 
    } else {
-      Object* oldObj = Vector_get(this->items, this->oldSelected);
+      const Object* oldObj = Vector_get(this->items, this->oldSelected);
       RichString_begin(old);
       Object_display(oldObj, &old);
       int oldLen = RichString_sizeVal(old);
-      Object* newObj = Vector_get(this->items, this->selected);
+      const Object* newObj = Vector_get(this->items, this->selected);
       RichString_begin(new);
       Object_display(newObj, &new);
       int newLen = RichString_sizeVal(new);
diff --git a/Panel.h b/Panel.h
index 945718ae..96c138d1 100644
--- a/Panel.h
+++ b/Panel.h
@@ -112,9 +112,9 @@ void Panel_moveSelectedUp(Panel* this);
 
 void Panel_moveSelectedDown(Panel* this);
 
-int Panel_getSelectedIndex(Panel* this);
+int Panel_getSelectedIndex(const Panel* this);
 
-int Panel_size(Panel* this);
+int Panel_size(const Panel* this);
 
 void Panel_setSelected(Panel* this, int selected);
 
diff --git a/ProcessList.c b/ProcessList.c
index 055ad1f1..585a9194 100644
--- a/ProcessList.c
+++ b/ProcessList.c
@@ -93,7 +93,7 @@ static const char* alignedProcessFieldTitle(ProcessField field) {
    return titleBuffer;
 }
 
-void ProcessList_printHeader(ProcessList* this, RichString* header) {
+void ProcessList_printHeader(const ProcessList* this, RichString* header) {
    RichString_prune(header);
 
    const Settings* settings = this->settings;
@@ -141,11 +141,11 @@ void ProcessList_add(ProcessList* this, Process* p) {
    assert(Hashtable_count(this->processTable) == Vector_count(this->processes));
 }
 
-void ProcessList_remove(ProcessList* this, Process* p) {
+void ProcessList_remove(ProcessList* this, const Process* p) {
    assert(Vector_indexOf(this->processes, p, Process_pidCompare) != -1);
    assert(Hashtable_get(this->processTable, p->pid) != NULL);
 
-   Process* pp = Hashtable_remove(this->processTable, p->pid);
+   const Process* pp = Hashtable_remove(this->processTable, p->pid);
    assert(pp == p); (void)pp;
 
    pid_t pid = p->pid;
@@ -169,7 +169,7 @@ Process* ProcessList_get(ProcessList* this, int idx) {
    return (Process*)Vector_get(this->processes, idx);
 }
 
-int ProcessList_size(ProcessList* this) {
+int ProcessList_size(const ProcessList* this) {
    return Vector_size(this->processes);
 }
 
diff --git a/ProcessList.h b/ProcessList.h
index b7ae4006..a2e17a16 100644
--- a/ProcessList.h
+++ b/ProcessList.h
@@ -85,15 +85,15 @@ void ProcessList_done(ProcessList* this);
 
 void ProcessList_setPanel(ProcessList* this, Panel* panel);
 
-void ProcessList_printHeader(ProcessList* this, RichString* header);
+void ProcessList_printHeader(const ProcessList* this, RichString* header);
 
 void ProcessList_add(ProcessList* this, Process* p);
 
-void ProcessList_remove(ProcessList* this, Process* p);
+void ProcessList_remove(ProcessList* this, const Process* p);
 
 Process* ProcessList_get(ProcessList* this, int idx);
 
-int ProcessList_size(ProcessList* this);
+int ProcessList_size(const ProcessList* this);
 
 void ProcessList_sort(ProcessList* this);
 
diff --git a/RichString.c b/RichString.c
index 01305806..ee06dce3 100644
--- a/RichString.c
+++ b/RichString.c
@@ -80,9 +80,9 @@ inline void RichString_setAttrn(RichString* this, int attrs, int start, int char
    }
 }
 
-int RichString_findChar(RichString* this, char c, int start) {
-   wchar_t wc = btowc(c);
-   cchar_t* ch = this->chptr + start;
+int RichString_findChar(const RichString* this, char c, int start) {
+   const wchar_t wc = btowc(c);
+   const cchar_t* ch = this->chptr + start;
    for (int i = start; i < this->chlen; i++) {
       if (ch->chars[0] == wc)
          return i;
@@ -115,8 +115,8 @@ void RichString_setAttrn(RichString* this, int attrs, int start, int charcount)
    }
 }
 
-int RichString_findChar(RichString* this, char c, int start) {
-   chtype* ch = this->chptr + start;
+int RichString_findChar(const RichString* this, char c, int start) {
+   const chtype* ch = this->chptr + start;
    for (int i = start; i < this->chlen; i++) {
       if ((*ch & 0xff) == (chtype) c)
          return i;
diff --git a/RichString.h b/RichString.h
index 4145b0d0..594db23c 100644
--- a/RichString.h
+++ b/RichString.h
@@ -44,7 +44,7 @@ typedef struct RichString_ {
 
 void RichString_setAttrn(RichString* this, int attrs, int start, int charcount);
 
-int RichString_findChar(RichString* this, char c, int start);
+int RichString_findChar(const RichString* this, char c, int start);
 
 void RichString_prune(RichString* this);
 
diff --git a/ScreenManager.c b/ScreenManager.c
index 0ab5231b..64af535b 100644
--- a/ScreenManager.c
+++ b/ScreenManager.c
@@ -42,14 +42,14 @@ void ScreenManager_delete(ScreenManager* this) {
    free(this);
 }
 
-inline int ScreenManager_size(ScreenManager* this) {
+inline int ScreenManager_size(const ScreenManager* this) {
    return this->panelCount;
 }
 
 void ScreenManager_add(ScreenManager* this, Panel* item, int size) {
    int lastX = 0;
    if (this->panelCount > 0) {
-      Panel* last = (Panel*) Vector_get(this->panels, this->panelCount - 1);
+      const Panel* last = (const Panel*) Vector_get(this->panels, this->panelCount - 1);
       lastX = last->x + last->w + 1;
    }
    int height = LINES - this->y1 + this->y2;
@@ -181,7 +181,7 @@ void ScreenManager_run(ScreenManager* this, Panel** lastFocus, int* lastKey) {
                            if (panel == panelFocus || this->allowFocusChange) {
                               focus = i;
                               panelFocus = panel;
-                              Object* oldSelection = Panel_getSelected(panel);
+                              const Object* oldSelection = Panel_getSelected(panel);
                               Panel_setSelected(panel, mevent.y - panel->y + panel->scrollV - 1);
                               if (Panel_getSelected(panel) == oldSelection) {
                                  ch = KEY_RECLICK;
diff --git a/ScreenManager.h b/ScreenManager.h
index 7dda4fca..87627bf2 100644
--- a/ScreenManager.h
+++ b/ScreenManager.h
@@ -34,7 +34,7 @@ ScreenManager* ScreenManager_new(Header* header, const Settings* settings, const
 
 void ScreenManager_delete(ScreenManager* this);
 
-int ScreenManager_size(ScreenManager* this);
+int ScreenManager_size(const ScreenManager* this);
 
 void ScreenManager_add(ScreenManager* this, Panel* item, int size);
 
diff --git a/Settings.c b/Settings.c
index ef607f00..f252c10d 100644
--- a/Settings.c
+++ b/Settings.c
@@ -29,14 +29,14 @@ void Settings_delete(Settings* this) {
    free(this);
 }
 
-static void Settings_readMeters(Settings* this, char* line, int column) {
+static void Settings_readMeters(Settings* this, const char* line, int column) {
    char* trim = String_trim(line);
    char** ids = String_split(trim, ' ', NULL);
    free(trim);
    this->columns[column].names = ids;
 }
 
-static void Settings_readMeterModes(Settings* this, char* line, int column) {
+static void Settings_readMeterModes(Settings* this, const char* line, int column) {
    char* trim = String_trim(line);
    char** ids = String_split(trim, ' ', NULL);
    free(trim);
@@ -237,7 +237,7 @@ static bool Settings_read(Settings* this, const char* fileName, int initialCpuCo
    return didReadFields;
 }
 
-static void writeFields(FILE* fd, ProcessField* fields, const char* name) {
+static void writeFields(FILE* fd, const ProcessField* fields, const char* name) {
    fprintf(fd, "%s=", name);
    const char* sep = "";
    for (int i = 0; fields[i]; i++) {
@@ -370,7 +370,7 @@ Settings* Settings_new(int initialCpuCount) {
    }
 
    char* legacyDotfile = NULL;
-   char* rcfile = getenv("HTOPRC");
+   const char* rcfile = getenv("HTOPRC");
    if (rcfile) {
       this->filename = xStrdup(rcfile);
    } else {
diff --git a/TraceScreen.c b/TraceScreen.c
index da98e02f..68f56963 100644
--- a/TraceScreen.c
+++ b/TraceScreen.c
@@ -35,7 +35,7 @@ static const char* const TraceScreenKeys[] = {"F3", "F4", "F8", "F9", "Esc"};
 
 static const int TraceScreenEvents[] = {KEY_F(3), KEY_F(4), KEY_F(8), KEY_F(9), 27};
 
-TraceScreen* TraceScreen_new(Process* process) {
+TraceScreen* TraceScreen_new(const Process* process) {
    // This initializes all TraceScreen variables to "false" so only default = true ones need to be set below
    TraceScreen* this = xCalloc(1, sizeof(TraceScreen));
    Object_setClass(this, Class(TraceScreen));
diff --git a/TraceScreen.h b/TraceScreen.h
index 3a2902a1..fd34ceed 100644
--- a/TraceScreen.h
+++ b/TraceScreen.h
@@ -28,7 +28,7 @@ typedef struct TraceScreen_ {
 
 extern const InfoScreenClass TraceScreen_class;
 
-TraceScreen* TraceScreen_new(Process* process);
+TraceScreen* TraceScreen_new(const Process* process);
 
 void TraceScreen_delete(Object* cast);
 
diff --git a/XUtils.c b/XUtils.c
index 9ad8c224..3661714b 100644
--- a/XUtils.c
+++ b/XUtils.c
@@ -173,7 +173,7 @@ char* String_readLine(FILE* fd) {
    char* buffer = xMalloc(step + 1);
    char* at = buffer;
    for (;;) {
-      char* ok = fgets(at, step + 1, fd);
+      const char* ok = fgets(at, step + 1, fd);
       if (!ok) {
          free(buffer);
          return NULL;
diff --git a/linux/LinuxProcessList.c b/linux/LinuxProcessList.c
index d181aaf2..a8514e28 100644
--- a/linux/LinuxProcessList.c
+++ b/linux/LinuxProcessList.c
@@ -107,7 +107,7 @@ static void LinuxProcessList_initTtyDrivers(LinuxProcessList* this) {
    while (*at != '\0') {
       at = strchr(at, ' ');    // skip first token
       while (*at == ' ') at++; // skip spaces
-      char* token = at;        // mark beginning of path
+      const char* token = at;  // mark beginning of path
       at = strchr(at, ' ');    // find end of path
       *at = '\0'; at++;        // clear and skip
       ttyDrivers[numDrivers].path = xStrdup(token); // save
@@ -394,7 +394,7 @@ static void LinuxProcessList_readIoFile(LinuxProcess* process, openat_arg_t proc
    unsigned long long last_read = process->io_read_bytes;
    unsigned long long last_write = process->io_write_bytes;
    char* buf = buffer;
-   char* line = NULL;
+   const char* line;
    while ((line = strsep(&buf, "\n")) != NULL) {
       switch (line[0]) {
       case 'r':
@@ -486,7 +486,7 @@ static void LinuxProcessList_calcLibSize_helper(ATTR_UNUSED ht_key_t key, void*
    if (!value)
       return;
 
-   LibraryData* v = (LibraryData *)value;
+   const LibraryData* v = (const LibraryData *)value;
    uint64_t* d = (uint64_t *)data;
    if (!v->exec)
       return;
@@ -755,7 +755,7 @@ static void LinuxProcessList_readCGroupFile(LinuxProcess* process, openat_arg_t
    int left = PROC_LINE_LENGTH;
    while (!feof(file) && left > 0) {
       char buffer[PROC_LINE_LENGTH + 1];
-      char* ok = fgets(buffer, PROC_LINE_LENGTH, file);
+      const char* ok = fgets(buffer, PROC_LINE_LENGTH, file);
       if (!ok)
          break;
 
@@ -859,7 +859,7 @@ static void LinuxProcessList_readSecattrData(LinuxProcess* process, openat_arg_t
    }
 
    char buffer[PROC_LINE_LENGTH + 1];
-   char* res = fgets(buffer, sizeof(buffer), file);
+   const char* res = fgets(buffer, sizeof(buffer), file);
    fclose(file);
    if (!res) {
       free(process->secattr);
@@ -906,7 +906,7 @@ static void LinuxProcessList_readCwd(LinuxProcess* process, openat_arg_t procFd)
 static int handleNetlinkMsg(struct nl_msg* nlmsg, void* linuxProcess) {
    struct nlmsghdr* nlhdr;
    struct nlattr* nlattrs[TASKSTATS_TYPE_MAX + 1];
-   struct nlattr* nlattr;
+   const struct nlattr* nlattr;
    struct taskstats stats;
    int rem;
    LinuxProcess* lp = (LinuxProcess*) linuxProcess;
@@ -1663,7 +1663,7 @@ static inline double LinuxProcessList_scanCPUTime(LinuxProcessList* this) {
       // Depending on your kernel version,
       // 5, 7, 8 or 9 of these fields will be set.
       // The rest will remain at zero.
-      char* ok = fgets(buffer, PROC_LINE_LENGTH, file);
+      const char* ok = fgets(buffer, PROC_LINE_LENGTH, file);
       if (!ok) {
          buffer[0] = '\0';
       }
diff --git a/linux/Platform.c b/linux/Platform.c
index dd80ded7..23163212 100644
--- a/linux/Platform.c
+++ b/linux/Platform.c
@@ -131,13 +131,13 @@ void Platform_done(void) {
 static Htop_Reaction Platform_actionSetIOPriority(State* st) {
    Panel* panel = st->panel;
 
-   LinuxProcess* p = (LinuxProcess*) Panel_getSelected(panel);
+   const LinuxProcess* p = (const LinuxProcess*) Panel_getSelected(panel);
    if (!p)
       return HTOP_OK;
 
    IOPriority ioprio1 = p->ioPriority;
    Panel* ioprioPanel = IOPriorityPanel_new(ioprio1);
-   void* set = Action_pickFromVector(st, ioprioPanel, 21, true);
+   const void* set = Action_pickFromVector(st, ioprioPanel, 21, true);
    if (set) {
       IOPriority ioprio2 = IOPriorityPanel_getIOPriority(ioprioPanel);
       bool ok = MainPanel_foreachProcess((MainPanel*)panel, LinuxProcess_setIOPriority, (Arg) { .i = ioprio2 }, NULL);
@@ -366,7 +366,7 @@ char* Platform_getProcessEnv(pid_t pid) {
  */
 char* Platform_getInodeFilename(pid_t pid, ino_t inode) {
    struct stat sb;
-   struct dirent *de;
+   const struct dirent *de;
    DIR *dirp;
    ssize_t len;
    int fd;
@@ -596,11 +596,11 @@ static unsigned long int parseBatInfo(const char* fileName, const unsigned short
    memset(batteries, 0, MAX_BATTERIES * sizeof(char*));
 
    while (nBatteries < MAX_BATTERIES) {
-      struct dirent* dirEntry = readdir(batteryDir);
+      const struct dirent* dirEntry = readdir(batteryDir);
       if (!dirEntry)
          break;
 
-      char* entryName = dirEntry->d_name;
+      const char* entryName = dirEntry->d_name;
       if (!String_startsWith(entryName, "BAT"))
          continue;
 
@@ -653,7 +653,7 @@ static ACPresence procAcpiCheck(void) {
       return AC_ERROR;
 
    for (;;) {
-      struct dirent* dirEntry = readdir(dir);
+      const struct dirent* dirEntry = readdir(dir);
       if (!dirEntry)
          break;
 
@@ -728,7 +728,7 @@ static void Platform_Battery_getSysData(double* percent, ACPresence* isOnAC) {
    unsigned long int totalRemain = 0;
 
    for (;;) {
-      struct dirent* dirEntry = readdir(dir);
+      const struct dirent* dirEntry = readdir(dir);
       if (!dirEntry)
          break;