Index: boost/program_options/errors.hpp
===================================================================
--- boost/program_options/errors.hpp	(Revision 57020)
+++ boost/program_options/errors.hpp	(Arbeitskopie)
@@ -38,6 +38,14 @@
         std::string tokens, msg;
     };
 
+    /** Class thrown when a required/mandatory option is missing */
+    class BOOST_PROGRAM_OPTIONS_DECL required_option : public error {
+    public:
+       required_option(const std::string& name)
+       : error(std::string("missing required option ").append(name))
+       {}
+    };
+
     /** Class thrown when option name is not recognized. */
     class BOOST_PROGRAM_OPTIONS_DECL unknown_option : public error {
     public:
Index: boost/program_options/value_semantic.hpp
===================================================================
--- boost/program_options/value_semantic.hpp	(Revision 57020)
+++ boost/program_options/value_semantic.hpp	(Arbeitskopie)
@@ -44,6 +44,11 @@
         */
         virtual bool is_composing() const = 0;
         
+        /** Returns true if value must be given. Non-optional value
+
+        */
+        virtual bool is_required() const = 0;
+
         /** Parses a group of tokens that specify a value of option.
             Stores the result in 'value_store', using whatever representation
             is desired. May be be called several times if value of the same
@@ -132,6 +137,8 @@
 
         bool is_composing() const { return false; }
         
+        bool is_required() const { return false; }
+
         /** If 'value_store' is already initialized, or new_tokens
             has more than one elements, throws. Otherwise, assigns
             the first string from 'new_tokens' to 'value_store', without
@@ -177,7 +184,8 @@
             the value when it's known. The parameter can be NULL. */
         typed_value(T* store_to) 
         : m_store_to(store_to), m_composing(false),
-          m_multitoken(false), m_zero_tokens(false)
+          m_multitoken(false), m_zero_tokens(false),
+          m_required(false)
         {} 
 
         /** Specifies default value, which will be used
@@ -265,6 +273,12 @@
             m_zero_tokens = true;
             return this;
         }
+
+        typed_value* required()
+        {
+            m_required = true;
+            return this;
+        }
             
 
     public: // value semantic overrides
@@ -292,7 +306,9 @@
             }
         }
 
+        bool is_required() const { return m_required; }
 
+
         /** Creates an instance of the 'validator' class and calls
             its operator() to perform the actual conversion. */
         void xparse(boost::any& value_store, 
@@ -335,7 +351,7 @@
         std::string m_default_value_as_text;
         boost::any m_implicit_value;
         std::string m_implicit_value_as_text;
-        bool m_composing, m_implicit, m_multitoken, m_zero_tokens;
+        bool m_composing, m_implicit, m_multitoken, m_zero_tokens, m_required;
         boost::function1<void, const T&> m_notifier;
     };
 
Index: libs/program_options/src/value_semantic.cpp
===================================================================
--- libs/program_options/src/value_semantic.cpp	(Revision 57020)
+++ libs/program_options/src/value_semantic.cpp	(Arbeitskopie)
@@ -171,13 +171,15 @@
         check_first_occurrence(v);
         string s(get_single_string(xs));
         if (!s.empty() && (
-                (*s.begin() == '\'' && *s.rbegin() == '\'' ||
-                 *s.begin() == '"' && *s.rbegin() == '"')))
+                ((*s.begin() == '\'' && *s.rbegin() == '\'') ||
+                 (*s.begin() == '"' && *s.rbegin() == '"'))))
         {
             v = any(s.substr(1, s.size()-2));
         }
         else
+        {
             v = any(s);
+        }
     }
 
 #if !defined(BOOST_NO_STD_WSTRING)
@@ -186,8 +188,8 @@
     {
         check_first_occurrence(v);
         wstring s(get_single_string(xs));
-        if (*s.begin() == L'\'' && *s.rbegin() == L'\'' ||
-            *s.begin() == L'"' && *s.rbegin() == L'"')
+        if ((*s.begin() == L'\'' && *s.rbegin() == L'\'') ||
+            (*s.begin() == L'"' && *s.rbegin() == L'"'))
             v = any(s.substr(1, s.size()-2));
         else
             v = any(s);
Index: libs/program_options/src/cmdline.cpp
===================================================================
--- libs/program_options/src/cmdline.cpp	(Revision 57020)
+++ libs/program_options/src/cmdline.cpp	(Arbeitskopie)
@@ -309,8 +309,25 @@
             }
         }
         result.swap(result2);
-        
 
+        // This checks if all required options occur
+        const std::vector< shared_ptr<option_description> >&
+                                         all_options = m_desc->options();
+        for (unsigned i = 0; i < all_options.size(); ++i) {
+           if (all_options[i]->semantic()->is_required()) {
+              bool found_required = false;
+              for (unsigned j = 0; !found_required && j < result.size(); ++j) {
+                 if (all_options[i]->key(result[j].string_key) == result[j].string_key) { // REVISIT, is this compare ok?
+                    found_required = true;
+                 }
+              }
+              if (!found_required) {
+                 boost::throw_exception(required_option(
+                                            all_options[i]->format_name()));
+              }
+           }
+        }
+
         // Assign position keys to positional options.
         int position_key = 0;
         for(unsigned i = 0; i < result.size(); ++i) {