diff --git a/BatteryMeter.c b/BatteryMeter.c
index 1690a969..f7323aa9 100644
--- a/BatteryMeter.c
+++ b/BatteryMeter.c
@@ -45,7 +45,7 @@ static unsigned long int parseUevent(FILE * file, const char *key) {
 }
 
 static unsigned long int parseBatInfo(const char *fileName, const unsigned short int lineNum, const unsigned short int wordNum) {
-   const DIR *batteryDir;
+   DIR* batteryDir;
    const struct dirent *dirEntries;
 
    const char batteryPath[] = PROCDIR "/acpi/battery/";
@@ -89,6 +89,7 @@ static unsigned long int parseBatInfo(const char *fileName, const unsigned short
       snprintf((char *) infoPath, sizeof infoPath, "%s%s/%s", batteryPath, newEntry->content, fileName);
 
       if ((file = fopen(infoPath, "r")) == NULL) {
+         closedir(batteryDir);
          return 0;
       }
 
@@ -107,7 +108,7 @@ static unsigned long int parseBatInfo(const char *fileName, const unsigned short
 
    free(myList);
    free(newEntry);
-   closedir((DIR *) batteryDir);
+   closedir(batteryDir);
    return total;
 }
 
@@ -274,6 +275,7 @@ static double getSysBatData() {
       } else {
          //reset file pointer
          if (fseek(file, 0, SEEK_SET) < 0) {
+            closedir(power_supplyDir);
             fclose(file);
             return 0;
          }
@@ -285,6 +287,7 @@ static double getSysBatData() {
       } else {
         //reset file pointer
          if (fseek(file, 0, SEEK_SET) < 0) {
+            closedir(power_supplyDir);
             fclose(file);
             return 0;
          }
diff --git a/LoadAverageMeter.c b/LoadAverageMeter.c
index 7646ad65..02c8ad5e 100644
--- a/LoadAverageMeter.c
+++ b/LoadAverageMeter.c
@@ -23,7 +23,7 @@ static inline void LoadAverageMeter_scan(double* one, double* five, double* fift
    *one = 0; *five = 0; *fifteen = 0;
    FILE *fd = fopen(PROCDIR "/loadavg", "r");
    if (fd) {
-      int total = fscanf(fd, "%lf %lf %lf %d/%d %d", one, five, fifteen,
+      int total = fscanf(fd, "%32lf %32lf %32lf %32d/%32d %32d", one, five, fifteen,
          &activeProcs, &totalProcs, &lastProc);
       (void) total;
       assert(total == 6);
diff --git a/Makefile.am b/Makefile.am
index 1c09ae90..919c987a 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -14,7 +14,7 @@ applications_DATA = htop.desktop
 pixmapdir = $(datadir)/pixmaps
 pixmap_DATA = htop.png
 
-htop_CFLAGS = -pedantic -Wall -std=c99 -rdynamic -D_XOPEN_SOURCE_EXTENDED
+htop_CFLAGS = -pedantic -Wall -Wextra -std=c99 -rdynamic -D_XOPEN_SOURCE_EXTENDED
 AM_CFLAGS = 
 AM_CPPFLAGS = -DSYSCONFDIR=\"$(sysconfdir)\"
 
diff --git a/Meter.c b/Meter.c
index 57862364..8c3cc50f 100644
--- a/Meter.c
+++ b/Meter.c
@@ -5,7 +5,6 @@ Released under the GNU GPL, see the COPYING file
 in the source distribution for its full text.
 */
 
-#define _GNU_SOURCE
 #include "RichString.h"
 #include "Meter.h"
 #include "Object.h"
@@ -275,11 +274,10 @@ static void BarMeterMode_draw(Meter* this, int x, int y, int w) {
    for (int i = 0; i < w; i++)
       bar[i] = ' ';
 
-   const size_t barOffset = w - MIN(strlen(buffer), w);
+   const size_t barOffset = w - MIN((int)strlen(buffer), w);
    snprintf(bar + barOffset, w - barOffset + 1, "%s", buffer);
 
    // First draw in the bar[] buffer...
-   double total = 0.0;
    int offset = 0;
    for (int i = 0; i < type->items; i++) {
       double value = this->values[i];
@@ -302,7 +300,6 @@ static void BarMeterMode_draw(Meter* this, int x, int y, int w) {
             }
          }
       offset = nextOffset;
-      total += this->values[i];
    }
 
    // ...then print the buffer.
diff --git a/Object.c b/Object.c
index 4e61c543..f8eb20db 100644
--- a/Object.c
+++ b/Object.c
@@ -48,10 +48,4 @@ void Object_setClass(void* this, char* class) {
    ((Object*)this)->class = class;
 }
 
-static void Object_display(Object* this, RichString* out) {
-   char objAddress[50];
-   sprintf(objAddress, "%s @ %p", this->class, (void*) this);
-   RichString_write(out, CRT_colors[DEFAULT_COLOR], objAddress);
-}
-
 #endif
diff --git a/Process.c b/Process.c
index a64bdd77..0632278a 100644
--- a/Process.c
+++ b/Process.c
@@ -235,7 +235,7 @@ void Process_getMaxPid() {
    FILE* file = fopen(PROCDIR "/sys/kernel/pid_max", "r");
    if (!file) return;
    int maxPid = 4194303;
-   fscanf(file, "%d", &maxPid);
+   fscanf(file, "%32d", &maxPid);
    fclose(file);
    if (maxPid > 99999) {
       Process_fieldTitles[PID] =   "    PID ";
@@ -287,7 +287,7 @@ static void Process_humanNumber(Process* this, RichString* str, unsigned long nu
    }
 }
 
-static void Process_colorNumber(Process* this, RichString* str, unsigned long long number) {
+static void Process_colorNumber(RichString* str, unsigned long long number) {
    char buffer[14];
    if (number > 10000000000) {
       snprintf(buffer, 13, "%11lld ", number / 1000);
@@ -486,8 +486,8 @@ static void Process_writeField(Process* this, RichString* str, ProcessField fiel
    case WCHAR:  snprintf(buffer, n, "%12llu ", this->io_wchar); break;   
    case SYSCR:  snprintf(buffer, n, "%10llu ", this->io_syscr); break;   
    case SYSCW:  snprintf(buffer, n, "%10llu ", this->io_syscw); break; 
-   case RBYTES: Process_colorNumber(this, str, this->io_read_bytes); return;
-   case WBYTES: Process_colorNumber(this, str, this->io_write_bytes); return;
+   case RBYTES: Process_colorNumber(str, this->io_read_bytes); return;
+   case WBYTES: Process_colorNumber(str, this->io_write_bytes); return;
    case CNCLWB: snprintf(buffer, n, "%10llu ", this->io_cancelled_write_bytes); break; 
    case IO_READ_RATE:  Process_outputRate(this, str, attr, buffer, n, this->io_rate_read_bps); return;
    case IO_WRITE_RATE: Process_outputRate(this, str, attr, buffer, n, this->io_rate_write_bps); return;
diff --git a/ProcessList.c b/ProcessList.c
index f3cc40f1..c986cecd 100644
--- a/ProcessList.c
+++ b/ProcessList.c
@@ -438,7 +438,7 @@ static bool ProcessList_readStatmFile(Process* process, const char* dirname, con
    if (!file)
       return false;
 
-   int num = fscanf(file, "%d %d %d %d %d %d %d",
+   int num = fscanf(file, "%32d %32d %32d %32d %32d %32d %32d",
        &process->m_size, &process->m_resident, &process->m_share, 
        &process->m_trs, &process->m_lrs, &process->m_drs, 
        &process->m_dt);
@@ -460,13 +460,13 @@ static void ProcessList_readOpenVZData(Process* process, const char* dirname, co
    if (!file) 
       return;
    fscanf(file, 
-      "%*u %*s %*c %*u %*u %*u %*u %*u %*u %*u "
-      "%*u %*u %*u %*u %*u %*u %*u %*u "
-      "%*u %*u %*u %*u %*u %*u %*u %*u "
-      "%*u %*u %*u %*u %*u %*u %*u %*u "
-      "%*u %*u %*u %*u %*u %*u %*u %*u "
-      "%*u %*u %*u %*u %*u %*u %*u "
-      "%*u %*u %u %u",
+      "%*32u %*32s %*1c %*32u %*32u %*32u %*32u %*32u %*32u %*32u "
+      "%*32u %*32u %*32u %*32u %*32u %*32u %*32u %*32u "
+      "%*32u %*32u %*32u %*32u %*32u %*32u %*32u %*32u "
+      "%*32u %*32u %*32u %*32u %*32u %*32u %*32u %*32u "
+      "%*32u %*32u %*32u %*32u %*32u %*32u %*32u %*32u "
+      "%*32u %*32u %*32u %*32u %*32u %*32u %*32u "
+      "%*32u %*32u %32u %32u",
       &process->vpid, &process->ctid);
    fclose(file);
 }
diff --git a/UptimeMeter.c b/UptimeMeter.c
index d676850d..3aa78977 100644
--- a/UptimeMeter.c
+++ b/UptimeMeter.c
@@ -22,7 +22,7 @@ static void UptimeMeter_setValues(Meter* this, char* buffer, int len) {
    double uptime = 0;
    FILE* fd = fopen(PROCDIR "/uptime", "r");
    if (fd) {
-      fscanf(fd, "%lf", &uptime);
+      fscanf(fd, "%64lf", &uptime);
       fclose(fd);
    }
    int totalseconds = (int) ceil(uptime);