diff --git a/src/signal_handler.cc b/src/signal_handler.cc
index 35e464c6..4b5eb55b 100644
--- a/src/signal_handler.cc
+++ b/src/signal_handler.cc
@@ -43,8 +43,8 @@ SignalHandler::Slot SignalHandler::m_handlers[HIGHEST_SIGNAL];
 
 void
 SignalHandler::set_default(unsigned int signum) {
-  if (signum >= HIGHEST_SIGNAL)
-    throw std::logic_error("SignalHandler::clear(...) received invalid signal value");
+  if (signum > HIGHEST_SIGNAL)
+    throw std::logic_error("SignalHandler::set_default(...) received invalid signal value.");
 
   signal(signum, SIG_DFL);
   m_handlers[signum].disconnect();
@@ -52,8 +52,8 @@ SignalHandler::set_default(unsigned int signum) {
 
 void
 SignalHandler::set_ignore(unsigned int signum) {
-  if (signum >= HIGHEST_SIGNAL)
-    throw std::logic_error("SignalHandler::clear(...) received invalid signal value");
+  if (signum > HIGHEST_SIGNAL)
+    throw std::logic_error("SignalHandler::set_ignore(...) received invalid signal value.");
 
   signal(signum, SIG_IGN);
   m_handlers[signum].disconnect();
@@ -61,11 +61,11 @@ SignalHandler::set_ignore(unsigned int signum) {
 
 void
 SignalHandler::set_handler(unsigned int signum, Slot slot) {
-  if (signum >= HIGHEST_SIGNAL)
-    throw std::logic_error("SignalHandler::handle(...) received invalid signal value");
+  if (signum > HIGHEST_SIGNAL)
+    throw std::logic_error("SignalHandler::set_handler(...) received invalid signal value.");
 
   if (slot.empty())
-    throw std::logic_error("SignalHandler::handle(...) received an empty slot");
+    throw std::logic_error("SignalHandler::set_handler(...) received an empty slot.");
 
   signal(signum, &SignalHandler::caught);
   m_handlers[signum] = slot;
@@ -73,11 +73,11 @@ SignalHandler::set_handler(unsigned int signum, Slot slot) {
 
 void
 SignalHandler::caught(int signum) {
-  if ((unsigned)signum >= HIGHEST_SIGNAL)
-    throw std::logic_error("SignalHandler::caught(...) received invalid signal from the kernel, bork bork bork");
+  if ((unsigned)signum > HIGHEST_SIGNAL)
+    throw std::logic_error("SignalHandler::caught(...) received invalid signal from the kernel, bork bork bork.");
 
   if (m_handlers[signum].empty())
-    throw std::logic_error("SignalHandler::caught(...) received a signal we don't have a handler for");
+    throw std::logic_error("SignalHandler::caught(...) received a signal we don't have a handler for.");
 
   m_handlers[signum]();
 }
diff --git a/src/signal_handler.h b/src/signal_handler.h
index 1ed060a5..60e44b22 100644
--- a/src/signal_handler.h
+++ b/src/signal_handler.h
@@ -44,8 +44,13 @@ class SignalHandler {
 public:
   typedef sigc::slot0<void> Slot;
 
-  static const unsigned int HIGHEST_SIGNAL = SIGUSR2;
-  
+#ifdef SIGRTMAX
+  static const unsigned int HIGHEST_SIGNAL = SIGRTMAX;
+#else  
+  // Let's be on the safe side.
+  static const unsigned int HIGHEST_SIGNAL = 64;
+#endif
+
   static void         set_default(unsigned int signum);
   static void         set_ignore(unsigned int signum);
   static void         set_handler(unsigned int signum, Slot slot);