diff --git a/FunctionBar.c b/FunctionBar.c
index 55279c21..df1fab8f 100644
--- a/FunctionBar.c
+++ b/FunctionBar.c
@@ -40,18 +40,18 @@ FunctionBar* FunctionBar_new(const char* const* functions, const char* const* ke
    }
    if (keys && events) {
       this->staticData = false;
-      this->keys = xCalloc(15, sizeof(char*));
+      this->keys.keys = xCalloc(15, sizeof(char*));
       this->events = xCalloc(15, sizeof(int));
       int i = 0;
       while (i < 15 && functions[i]) {
-         this->keys[i] = xStrdup(keys[i]);
+         this->keys.keys[i] = xStrdup(keys[i]);
          this->events[i] = events[i];
          i++;
       }
       this->size = i;
    } else {
       this->staticData = true;
-      this->keys = (char**) FunctionBar_FKeys;
+      this->keys.constKeys = FunctionBar_FKeys;
       this->events = FunctionBar_FEvents;
       this->size = 10;
    }
@@ -65,9 +65,9 @@ void FunctionBar_delete(FunctionBar* this) {
    free(this->functions);
    if (!this->staticData) {
       for (int i = 0; i < this->size; i++) {
-         free(this->keys[i]);
+         free(this->keys.keys[i]);
       }
-      free(this->keys);
+      free(this->keys.keys);
       free(this->events);
    }
    free(this);
@@ -93,8 +93,8 @@ void FunctionBar_drawAttr(const FunctionBar* this, char* buffer, int attr) {
    int x = 0;
    for (int i = 0; i < this->size; i++) {
       attrset(CRT_colors[FUNCTION_KEY]);
-      mvaddstr(LINES-1, x, this->keys[i]);
-      x += strlen(this->keys[i]);
+      mvaddstr(LINES-1, x, this->keys.constKeys[i]);
+      x += strlen(this->keys.constKeys[i]);
       attrset(CRT_colors[FUNCTION_BAR]);
       mvaddstr(LINES-1, x, this->functions[i]);
       x += strlen(this->functions[i]);
@@ -113,7 +113,7 @@ void FunctionBar_drawAttr(const FunctionBar* this, char* buffer, int attr) {
 int FunctionBar_synthesizeEvent(const FunctionBar* this, int pos) {
    int x = 0;
    for (int i = 0; i < this->size; i++) {
-      x += strlen(this->keys[i]);
+      x += strlen(this->keys.constKeys[i]);
       x += strlen(this->functions[i]);
       if (pos < x) {
          return this->events[i];
diff --git a/FunctionBar.h b/FunctionBar.h
index 8fa74404..c650c1a4 100644
--- a/FunctionBar.h
+++ b/FunctionBar.h
@@ -12,7 +12,10 @@ in the source distribution for its full text.
 typedef struct FunctionBar_ {
    int size;
    char** functions;
-   char** keys;
+   union {
+      char** keys;
+      const char* const* constKeys;
+   } keys;
    int* events;
    bool staticData;
 } FunctionBar;
diff --git a/Macros.h b/Macros.h
index 33e727d8..bb3a90e0 100644
--- a/Macros.h
+++ b/Macros.h
@@ -33,4 +33,20 @@
 
 #endif /* __GNUC__ */
 
+// ignore casts discarding const specifier, e.g.
+//     const char []     ->  char * / void *
+//     const char *[2]'  ->  char *const *
+#ifdef __clang__
+#define IGNORE_WCASTQUAL_BEGIN  _Pragma("clang diagnostic push") \
+                                _Pragma("clang diagnostic ignored \"-Wcast-qual\"")
+#define IGNORE_WCASTQUAL_END    _Pragma("clang diagnostic pop")
+#elif defined(__GNUC__)
+#define IGNORE_WCASTQUAL_BEGIN  _Pragma("GCC diagnostic push") \
+                                _Pragma("GCC diagnostic ignored \"-Wcast-qual\"")
+#define IGNORE_WCASTQUAL_END    _Pragma("GCC diagnostic pop")
+#else
+#define IGNORE_WCASTQUAL_BEGIN
+#define IGNORE_WCASTQUAL_END
+#endif
+
 #endif
diff --git a/configure.ac b/configure.ac
index ce4e96b4..7982d648 100644
--- a/configure.ac
+++ b/configure.ac
@@ -296,6 +296,7 @@ fi
 AM_CFLAGS="\
  -Wall\
  -Wcast-align\
+ -Wcast-qual\
  -Wextra\
  -Wfloat-equal\
  -Wmissing-format-attribute\
diff --git a/dragonflybsd/DragonFlyBSDProcess.c b/dragonflybsd/DragonFlyBSDProcess.c
index 972c77c2..df320e08 100644
--- a/dragonflybsd/DragonFlyBSDProcess.c
+++ b/dragonflybsd/DragonFlyBSDProcess.c
@@ -108,14 +108,14 @@ void DragonFlyBSDProcess_writeField(Process* this, RichString* str, ProcessField
 }
 
 long DragonFlyBSDProcess_compare(const void* v1, const void* v2) {
-   DragonFlyBSDProcess *p1, *p2;
-   Settings *settings = ((Process*)v1)->settings;
+   const DragonFlyBSDProcess *p1, *p2;
+   const Settings *settings = ((const Process*)v1)->settings;
    if (settings->direction == 1) {
-      p1 = (DragonFlyBSDProcess*)v1;
-      p2 = (DragonFlyBSDProcess*)v2;
+      p1 = (const DragonFlyBSDProcess*)v1;
+      p2 = (const DragonFlyBSDProcess*)v2;
    } else {
-      p2 = (DragonFlyBSDProcess*)v1;
-      p1 = (DragonFlyBSDProcess*)v2;
+      p2 = (const DragonFlyBSDProcess*)v1;
+      p1 = (const DragonFlyBSDProcess*)v2;
    }
    switch ((int) settings->sortKey) {
    // add Platform-specific fields here
diff --git a/freebsd/FreeBSDProcess.c b/freebsd/FreeBSDProcess.c
index 399c5f69..767f485b 100644
--- a/freebsd/FreeBSDProcess.c
+++ b/freebsd/FreeBSDProcess.c
@@ -107,14 +107,14 @@ void FreeBSDProcess_writeField(Process* this, RichString* str, ProcessField fiel
 }
 
 long FreeBSDProcess_compare(const void* v1, const void* v2) {
-   FreeBSDProcess *p1, *p2;
-   Settings *settings = ((Process*)v1)->settings;
+   const FreeBSDProcess *p1, *p2;
+   const Settings *settings = ((const Process*)v1)->settings;
    if (settings->direction == 1) {
-      p1 = (FreeBSDProcess*)v1;
-      p2 = (FreeBSDProcess*)v2;
+      p1 = (const FreeBSDProcess*)v1;
+      p2 = (const FreeBSDProcess*)v2;
    } else {
-      p2 = (FreeBSDProcess*)v1;
-      p1 = (FreeBSDProcess*)v2;
+      p2 = (const FreeBSDProcess*)v1;
+      p1 = (const FreeBSDProcess*)v2;
    }
    switch ((int) settings->sortKey) {
    // add FreeBSD-specific fields here
diff --git a/freebsd/FreeBSDProcessList.c b/freebsd/FreeBSDProcessList.c
index cd9897fb..f9377a2d 100644
--- a/freebsd/FreeBSDProcessList.c
+++ b/freebsd/FreeBSDProcessList.c
@@ -5,6 +5,7 @@ Released under the GNU GPLv2, see the COPYING file
 in the source distribution for its full text.
 */
 
+#include "Macros.h"
 #include "ProcessList.h"
 #include "FreeBSDProcessList.h"
 #include "FreeBSDProcess.h"
@@ -338,6 +339,7 @@ char* FreeBSDProcessList_readJailName(struct kinfo_proc* kproc) {
 
    if (kproc->ki_jid != 0 ){
       memset(jnamebuf, 0, sizeof(jnamebuf));
+IGNORE_WCASTQUAL_BEGIN
       *(const void **)&jiov[0].iov_base = "jid";
       jiov[0].iov_len = sizeof("jid");
       jiov[1].iov_base = &kproc->ki_jid;
@@ -350,6 +352,7 @@ char* FreeBSDProcessList_readJailName(struct kinfo_proc* kproc) {
       jiov[4].iov_len = sizeof("errmsg");
       jiov[5].iov_base = jail_errmsg;
       jiov[5].iov_len = JAIL_ERRMSGLEN;
+IGNORE_WCASTQUAL_END
       jail_errmsg[0] = 0;
       jid = jail_get(jiov, 6, 0);
       if (jid < 0) {
diff --git a/openbsd/OpenBSDProcess.c b/openbsd/OpenBSDProcess.c
index 6f52adf0..94ce4828 100644
--- a/openbsd/OpenBSDProcess.c
+++ b/openbsd/OpenBSDProcess.c
@@ -193,14 +193,14 @@ void OpenBSDProcess_writeField(Process* this, RichString* str, ProcessField fiel
 }
 
 long OpenBSDProcess_compare(const void* v1, const void* v2) {
-   OpenBSDProcess *p1, *p2;
-   Settings *settings = ((Process*)v1)->settings;
+   const OpenBSDProcess *p1, *p2;
+   const Settings *settings = ((const Process*)v1)->settings;
    if (settings->direction == 1) {
-      p1 = (OpenBSDProcess*)v1;
-      p2 = (OpenBSDProcess*)v2;
+      p1 = (const OpenBSDProcess*)v1;
+      p2 = (const OpenBSDProcess*)v2;
    } else {
-      p2 = (OpenBSDProcess*)v1;
-      p1 = (OpenBSDProcess*)v2;
+      p2 = (const OpenBSDProcess*)v1;
+      p1 = (const OpenBSDProcess*)v2;
    }
    switch (settings->sortKey) {
    // add OpenBSD-specific fields here
diff --git a/solaris/SolarisProcess.c b/solaris/SolarisProcess.c
index 89b1690d..d0a75dfe 100644
--- a/solaris/SolarisProcess.c
+++ b/solaris/SolarisProcess.c
@@ -117,14 +117,14 @@ void SolarisProcess_writeField(Process* this, RichString* str, ProcessField fiel
 }
 
 long SolarisProcess_compare(const void* v1, const void* v2) {
-   SolarisProcess *p1, *p2;
-   Settings* settings = ((Process*)v1)->settings;
+   const SolarisProcess *p1, *p2;
+   const Settings* settings = ((const Process*)v1)->settings;
    if (settings->direction == 1) {
-      p1 = (SolarisProcess*)v1;
-      p2 = (SolarisProcess*)v2;
+      p1 = (const SolarisProcess*)v1;
+      p2 = (const SolarisProcess*)v2;
    } else {
-      p2 = (SolarisProcess*)v1;
-      p1 = (SolarisProcess*)v2;
+      p2 = (const SolarisProcess*)v1;
+      p1 = (const SolarisProcess*)v2;
    }
    switch ((int) settings->sortKey) {
    case ZONEID: