diff --git a/Action.c b/Action.c
index 3f5737fc..5b68811e 100644
--- a/Action.c
+++ b/Action.c
@@ -93,20 +93,20 @@ static void Action_runSetup(State* st) {
 
 static bool changePriority(MainPanel* panel, int delta) {
    bool anyTagged;
-   bool ok = MainPanel_foreachProcess(panel, (MainPanel_ForeachProcessFn) Process_changePriorityBy, (Arg){ .i = delta }, &anyTagged);
+   bool ok = MainPanel_foreachProcess(panel, Process_changePriorityBy, (Arg){ .i = delta }, &anyTagged);
    if (!ok)
       beep();
    return anyTagged;
 }
 
 static void addUserToVector(int key, void* userCast, void* panelCast) {
-   char* user = (char*) userCast;
-   Panel* panel = (Panel*) panelCast;
+   const char* user = userCast;
+   Panel* panel = panelCast;
    Panel_add(panel, (Object*) ListItem_new(user, key));
 }
 
 bool Action_setUserOnly(const char* userName, uid_t* userId) {
-   struct passwd* user = getpwnam(userName);
+   const struct passwd* user = getpwnam(userName);
    if (user) {
       *userId = user->pw_uid;
       return true;
@@ -301,7 +301,7 @@ static Htop_Reaction actionSetAffinity(State* st) {
    void* set = Action_pickFromVector(st, affinityPanel, width, true);
    if (set) {
       Affinity* affinity2 = AffinityPanel_getAffinity(affinityPanel, st->pl);
-      bool ok = MainPanel_foreachProcess((MainPanel*)panel, (MainPanel_ForeachProcessFn) Affinity_set, (Arg){ .v = affinity2 }, NULL);
+      bool ok = MainPanel_foreachProcess((MainPanel*)panel, Affinity_set, (Arg){ .v = affinity2 }, NULL);
       if (!ok) beep();
       Affinity_delete(affinity2);
    }
@@ -318,7 +318,7 @@ static Htop_Reaction actionKill(State* st) {
          Panel_setHeader(st->panel, "Sending...");
          Panel_draw(st->panel, true);
          refresh();
-         MainPanel_foreachProcess((MainPanel*)st->panel, (MainPanel_ForeachProcessFn) Process_sendSignal, (Arg){ .i = sgn->key }, NULL);
+         MainPanel_foreachProcess((MainPanel*)st->panel, Process_sendSignal, (Arg){ .i = sgn->key }, NULL);
          napms(500);
       }
    }
diff --git a/Panel.c b/Panel.c
index 782cbdc1..02440d85 100644
--- a/Panel.c
+++ b/Panel.c
@@ -423,7 +423,7 @@ HandlerResult Panel_selectByTyping(Panel* this, int ch) {
       for (int try = 0; try < 2; try++) {
          len = strlen(buffer);
          for (int i = 0; i < size; i++) {
-            char* cur = ((ListItem*) Panel_get(this, i))->value;
+            const char* cur = ((ListItem*) Panel_get(this, i))->value;
             while (*cur == ' ') cur++;
             if (strncasecmp(cur, buffer, len) == 0) {
                Panel_setSelected(this, i);
diff --git a/UsersTable.c b/UsersTable.c
index 83c6dbc3..25e44883 100644
--- a/UsersTable.c
+++ b/UsersTable.c
@@ -30,9 +30,9 @@ void UsersTable_delete(UsersTable* this) {
 }
 
 char* UsersTable_getRef(UsersTable* this, unsigned int uid) {
-   char* name = (char*) (Hashtable_get(this->users, uid));
+   char* name = Hashtable_get(this->users, uid);
    if (name == NULL) {
-      struct passwd* userData = getpwuid(uid);
+      const struct passwd* userData = getpwuid(uid);
       if (userData != NULL) {
          name = xStrdup(userData->pw_name);
          Hashtable_put(this->users, uid, name);
diff --git a/linux/LinuxProcess.c b/linux/LinuxProcess.c
index 23783ef0..fad80555 100644
--- a/linux/LinuxProcess.c
+++ b/linux/LinuxProcess.c
@@ -179,12 +179,12 @@ IOPriority LinuxProcess_updateIOPriority(LinuxProcess* this) {
    return ioprio;
 }
 
-bool LinuxProcess_setIOPriority(LinuxProcess* this, Arg ioprio) {
+bool LinuxProcess_setIOPriority(Process* this, Arg ioprio) {
 // Other OSes masquerading as Linux (NetBSD?) don't have this syscall
 #ifdef SYS_ioprio_set
-   syscall(SYS_ioprio_set, IOPRIO_WHO_PROCESS, this->super.pid, ioprio.i);
+   syscall(SYS_ioprio_set, IOPRIO_WHO_PROCESS, this->pid, ioprio.i);
 #endif
-   return (LinuxProcess_updateIOPriority(this) == ioprio.i);
+   return (LinuxProcess_updateIOPriority((LinuxProcess*)this) == ioprio.i);
 }
 
 #ifdef HAVE_DELAYACCT
diff --git a/linux/LinuxProcess.h b/linux/LinuxProcess.h
index 45a3127f..80a4220b 100644
--- a/linux/LinuxProcess.h
+++ b/linux/LinuxProcess.h
@@ -183,7 +183,7 @@ extern io_priority;
 
 IOPriority LinuxProcess_updateIOPriority(LinuxProcess* this);
 
-bool LinuxProcess_setIOPriority(LinuxProcess* this, Arg ioprio);
+bool LinuxProcess_setIOPriority(Process* this, Arg ioprio);
 
 #ifdef HAVE_DELAYACCT
 void LinuxProcess_printDelay(float delay_percent, char* buffer, int n);
diff --git a/linux/LinuxProcessList.c b/linux/LinuxProcessList.c
index 5d9bc3c4..f7d01557 100644
--- a/linux/LinuxProcessList.c
+++ b/linux/LinuxProcessList.c
@@ -480,7 +480,6 @@ static bool LinuxProcessList_readSmapsFile(LinuxProcess* process, const char* di
    //kernel will return data in chunks of size PAGE_SIZE or less.
 
    char buffer[CRT_pageSize];// 4k
-   char *start,*end;
    ssize_t nread=0;
    if(haveSmapsRollup) {// only available in Linux 4.14+
       xSnprintf(buffer, sizeof(buffer), "%s/%s/smaps_rollup", dirname, name);
@@ -496,8 +495,8 @@ static bool LinuxProcessList_readSmapsFile(LinuxProcess* process, const char* di
    process->m_psswp = 0;
 
    while ( ( nread =  read(fd,buffer, sizeof(buffer)) ) > 0 ){
-        start = (char *)&buffer;
-        end   = start + nread;
+        char* start = buffer;
+        char* end   = start + nread;
         do{//parse 4k block
             int tmp;
 
diff --git a/linux/Platform.c b/linux/Platform.c
index 43bf84b1..f6f7ba19 100644
--- a/linux/Platform.c
+++ b/linux/Platform.c
@@ -103,7 +103,7 @@ static Htop_Reaction Platform_actionSetIOPriority(State* st) {
    void* set = Action_pickFromVector(st, ioprioPanel, 21, true);
    if (set) {
       IOPriority ioprio2 = IOPriorityPanel_getIOPriority(ioprioPanel);
-      bool ok = MainPanel_foreachProcess((MainPanel*)panel, (MainPanel_ForeachProcessFn) LinuxProcess_setIOPriority, (Arg){ .i = ioprio2 }, NULL);
+      bool ok = MainPanel_foreachProcess((MainPanel*)panel, LinuxProcess_setIOPriority, (Arg){ .i = ioprio2 }, NULL);
       if (!ok)
          beep();
    }