diff --git a/base/cprintf.cc b/base/cprintf.cc
index af3b26a577..5796a712bb 100644
--- a/base/cprintf.cc
+++ b/base/cprintf.cc
@@ -45,8 +45,6 @@ ArgList::dump(const string &format)
     stream->fill(' ');
     stream->flags((ios::fmtflags)0);
 
-    Format fmt;
-
     while (*p) {
         switch (*p) {
           case '%': {
@@ -56,12 +54,7 @@ ArgList::dump(const string &format)
                   continue;
               }
 
-              if (objects.empty())
-                  format_invalid(*stream);
-
-              Base *data = objects.front();
-
-              fmt.clear();
+              Format fmt;
               bool done = false;
               bool end_number = false;
               bool have_precision = false;
@@ -205,18 +198,26 @@ ArgList::dump(const string &format)
                   }
               }
 
-              ios::fmtflags saved_flags = stream->flags();
-              char old_fill = stream->fill();
-              int old_precision = stream->precision();
+              if (!objects.empty())
+              {
+                  Base *data = objects.front();
+                  objects.pop_front();
 
-              data->process(*stream, fmt);
+                  ios::fmtflags saved_flags = stream->flags();
+                  char old_fill = stream->fill();
+                  int old_precision = stream->precision();
 
-              stream->flags(saved_flags);
-              stream->fill(old_fill);
-              stream->precision(old_precision);
+                  data->process(*stream, fmt);
+
+                  stream->flags(saved_flags);
+                  stream->fill(old_fill);
+                  stream->precision(old_precision);
+
+                  delete data;
+              } else {
+                  *stream << "<missing arg for format>";
+              }
 
-              delete data;
-              objects.pop_front();
               ++p;
           }
             break;
@@ -241,10 +242,10 @@ ArgList::dump(const string &format)
     }
 
     while (!objects.empty()) {
+        *stream << "<extra arg>";
         Base *data = objects.front();
-        data->process(*stream, fmt);
-        delete data;
         objects.pop_front();
+        delete data;
     }
 }
 
diff --git a/base/cprintf.hh b/base/cprintf.hh
index 8360d227c5..ac34cd2521 100644
--- a/base/cprintf.hh
+++ b/base/cprintf.hh
@@ -75,7 +75,7 @@ class ArgList
                 break;
 
               default:
-                format_invalid(out);
+                out << "<bad format>";
                 break;
             }
         }
diff --git a/base/cprintf_formats.hh b/base/cprintf_formats.hh
index 1e5de4fdf8..b921c05062 100644
--- a/base/cprintf_formats.hh
+++ b/base/cprintf_formats.hh
@@ -43,8 +43,10 @@ struct Format
     int precision;
     int width;
 
-    Format() { }
-    void clear() {
+    Format() { clear(); }
+
+    void clear()
+    {
         alternate_form = false;
         flush_left = false;
         print_sign = false;
@@ -58,15 +60,6 @@ struct Format
     }
 };
 
-inline void
-format_invalid(std::ostream &out)
-{
-    using namespace std;
-
-    out << "format invalid!!!" << endl;
-}
-
-
 template <typename T>
 inline void
 _format_char(std::ostream &out, const T& data, Format &fmt)
@@ -233,7 +226,7 @@ _format_string(std::ostream &out, const T& data, Format &fmt)
 template <typename T>
 inline void
 format_char(std::ostream &out, const T& data, Format &fmt)
-{ format_invalid(out); }
+{ out << "<bad arg type for char format>"; }
 
 inline void
 format_char(std::ostream &out, char data, Format &fmt)
@@ -329,7 +322,7 @@ format_integer(std::ostream &out, unsigned long long data, Format &fmt)
 template <typename T>
 inline void
 format_float(std::ostream &out, const T& data, Format &fmt)
-{ format_invalid(out); }
+{ out << "<bad arg type for float format>"; }
 
 inline void
 format_float(std::ostream &out, float data, Format &fmt)