X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/3c22fdea313dc38d430071450a15015f0746632b..4bd1f48f0bf1ad1703be680ec2a38d626c6a2668:/src/xbt/config.cpp

diff --git a/src/xbt/config.cpp b/src/xbt/config.cpp
index 7c8619f8a3..d2f380be0c 100644
--- a/src/xbt/config.cpp
+++ b/src/xbt/config.cpp
@@ -1,511 +1,487 @@
-/* Copyright (c) 2004-2014,2016. The SimGrid Team.
- * All rights reserved.                                                     */
+/* Copyright (c) 2004-2017. The SimGrid Team. All rights reserved.     */
 
-#include <stdio.h>
+/* This program is free software; you can redistribute it and/or modify it
+ * under the terms of the license (GNU LGPL) which comes with this package. */
+
+#include <cstdio>
+
+#include <algorithm>
+#include <cerrno>
+#include <cstring>
+#include <climits>
 
 #include <functional>
+#include <map>
+#include <stdexcept>
 #include <string>
 #include <type_traits>
+#include <typeinfo>
+#include <vector>
 
+#include <xbt/ex.hpp>
 #include <xbt/config.h>
 #include <xbt/config.hpp>
 #include "xbt/misc.h"
 #include "xbt/sysdep.h"
 #include "xbt/log.h"
-#include "xbt/ex.h"
 #include "xbt/dynar.h"
-#include "xbt/dict.h"
-
-// *****
 
 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_cfg, xbt, "configuration support");
 
-XBT_EXPORT_NO_IMPORT(xbt_cfg_t) simgrid_config = NULL;
+XBT_EXPORT_NO_IMPORT(xbt_cfg_t) simgrid_config = nullptr;
+extern "C" {
+  XBT_PUBLIC(void) sg_config_finalize();
+}
+
+namespace simgrid {
+namespace config {
+
+missing_key_error::~missing_key_error() = default;
+
+class Config;
 
 namespace {
 
-// We could define some range/iterator for the num values.
-static inline
-void increment(e_xbt_cfgelm_type_t& type)
-{
-  typedef std::underlying_type<e_xbt_cfgelm_type_t>::type underlying_type;
-  type = (e_xbt_cfgelm_type_t) ((underlying_type) type + 1);
-}
+const char* true_values[] = {
+  "yes", "on", "true", "1"
+};
+const char* false_values[] = {
+  "no", "off", "false", "0"
+};
 
+static bool parseBool(const char* value)
+{
+  for (const char* const& true_value : true_values)
+    if (std::strcmp(true_value, value) == 0)
+      return true;
+  for (const char* const& false_value : false_values)
+    if (std::strcmp(false_value, value) == 0)
+      return false;
+  throw std::range_error("not a boolean");
+}
+
+static double parseDouble(const char* value)
+{
+  char* end;
+  errno = 0;
+  double res = std::strtod(value, &end);
+  if (errno == ERANGE)
+    throw std::range_error("out of range");
+  else if (errno)
+    xbt_die("Unexpected errno");
+  if (end == value || *end != '\0')
+    throw std::range_error("invalid double");
+  else
+    return res;
+}
+
+static long int parseLong(const char* value)
+{
+  char* end;
+  errno = 0;
+  long int res = std::strtol(value, &end, 0);
+  if (errno) {
+    if (res == LONG_MIN && errno == ERANGE)
+      throw std::range_error("underflow");
+    else if (res == LONG_MAX && errno == ERANGE)
+      throw std::range_error("overflow");
+    xbt_die("Unexpected errno");
+  }
+  if (end == value || *end != '\0')
+    throw std::range_error("invalid integer");
+  else
+    return res;
 }
 
-/* xbt_cfgelm_t: the typedef corresponding to a config variable. */
+// ***** ConfigType *****
+
+/// A trait which define possible options types:
+template<class T> struct ConfigType;
+
+template<> struct ConfigType<int> {
+  static constexpr const char* type_name = "int";
+  static inline double parse(const char* value)
+  {
+    return parseLong(value);
+  }
+};
+template<> struct ConfigType<double> {
+  static constexpr const char* type_name = "double";
+  static inline double parse(const char* value)
+  {
+    return parseDouble(value);
+  }
+};
+template<> struct ConfigType<std::string> {
+  static constexpr const char* type_name = "string";
+  static inline std::string parse(const char* value)
+  {
+    return std::string(value);
+  }
+};
+template<> struct ConfigType<bool> {
+  static constexpr const char* type_name = "boolean";
+  static inline bool parse(const char* value)
+  {
+    return parseBool(value);
+  }
+};
+
+// **** Forward declarations ****
+
+class ConfigurationElement ;
+template<class T> class TypedConfigurationElement;
+
+// **** ConfigurationElement ****
 
-typedef struct {
-  /* Description */
-  char *desc;
+class ConfigurationElement {
+protected:
+  std::string key;
+  std::string desc;
+  bool isdefault = true;
 
-  /* Allowed type of the variable */
-  e_xbt_cfgelm_type_t type;
-  unsigned isdefault:1;
+public:
+  /* Callback */
+  xbt_cfg_cb_t old_callback = nullptr;
 
-  /* Callbacks */
-  xbt_cfg_cb_t cb_set;
+  ConfigurationElement(const char* key, const char* desc)
+    : key(key ? key : ""), desc(desc ? desc : "") {}
+  ConfigurationElement(const char* key, const char* desc, xbt_cfg_cb_t cb)
+    : key(key ? key : ""), desc(desc ? desc : ""), old_callback(cb) {}
 
-  /* Advanced callbacks */
-  xbt_cfg_cb_ext_t cb_set_ext;
-  void* cb_set_data;
-  xbt_cfg_cb_free_t cb_set_free;
+  virtual ~ConfigurationElement()=default;
 
-  /* actual content (could be an union or something) */
-  xbt_dynar_t content;
-} s_xbt_cfgelm_t, *xbt_cfgelm_t;
+  virtual std::string getStringValue() = 0;
+  virtual void setStringValue(const char* value) = 0;
+  virtual const char* getTypeName() = 0;
 
-static const char *xbt_cfgelm_type_name[xbt_cfgelm_type_count] = { "int", "double", "string", "boolean", "any", "outofbound" };
+  template<class T>
+  T const& getValue() const
+  {
+    return dynamic_cast<const TypedConfigurationElement<T>&>(*this).getValue();
+  }
+  template<class T>
+  void setValue(T value)
+  {
+    dynamic_cast<TypedConfigurationElement<T>&>(*this).setValue(std::move(value));
+  }
+  template<class T>
+  void setDefaultValue(T value)
+  {
+    dynamic_cast<TypedConfigurationElement<T>&>(*this).setDefaultValue(std::move(value));
+  }
+  bool isDefault() const { return isdefault; }
 
-const struct xbt_boolean_couple xbt_cfgelm_boolean_values[] = {
-  { "yes",    "no"},
-  {  "on",   "off"},
-  {"true", "false"},
-  {   "1",     "0"},
-  {  NULL,    NULL}
+  std::string const& getDescription() const { return desc; }
+  std::string const& getKey() const { return key; }
 };
 
-/* Internal stuff used in cache to free a variable */
-static void xbt_cfgelm_free(void *data);
+// **** TypedConfigurationElement<T> ****
+
+// TODO, could we use boost::any with some Type* reference?
+template<class T>
+class TypedConfigurationElement : public ConfigurationElement {
+private:
+  T content;
+  std::function<void(T&)> callback;
+
+public:
+  TypedConfigurationElement(const char* key, const char* desc, T value = T())
+    : ConfigurationElement(key, desc), content(std::move(value))
+  {}
+  TypedConfigurationElement(const char* key, const char* desc, T value, xbt_cfg_cb_t cb)
+      : ConfigurationElement(key, desc, cb), content(std::move(value))
+  {}
+  TypedConfigurationElement(const char* key, const char* desc, T value, std::function<void(T&)> callback)
+      : ConfigurationElement(key, desc), content(std::move(value)), callback(std::move(callback))
+  {}
+  ~TypedConfigurationElement() = default;
+
+  std::string getStringValue() override;
+  const char* getTypeName() override;
+  void setStringValue(const char* value) override;
+
+  void update()
+  {
+    if (old_callback)
+      this->old_callback(key.c_str());
+    if (this->callback)
+      this->callback(this->content);
+  }
+
+  T const& getValue() const { return content; }
 
-/* Retrieve the variable we'll modify */
-static xbt_cfgelm_t xbt_cfgelm_get(xbt_cfg_t cfg, const char *name, e_xbt_cfgelm_type_t type);
+  void setValue(T value)
+  {
+    this->content = std::move(value);
+    this->update();
+  }
 
-/*----[ Memory management ]-----------------------------------------------*/
-/** @brief Constructor
- *
- * Initialise a config set
- */
-xbt_cfg_t xbt_cfg_new(void)
+  void setDefaultValue(T value)
+  {
+    if (this->isdefault) {
+      this->content = std::move(value);
+      this->update();
+    } else {
+      XBT_DEBUG("Do not override configuration variable '%s' with value '%s' because it was already set.", key.c_str(),
+                to_string(value).c_str());
+    }
+  }
+};
+
+template<class T>
+std::string TypedConfigurationElement<T>::getStringValue() // override
 {
-  return (xbt_cfg_t) xbt_dict_new_homogeneous(&xbt_cfgelm_free);
+  return to_string(content);
 }
 
-/** @brief Destructor */
-void xbt_cfg_free(xbt_cfg_t * cfg)
+template<class T>
+void TypedConfigurationElement<T>::setStringValue(const char* value) // override
 {
-  XBT_DEBUG("Frees cfg set %p", cfg);
-  xbt_dict_free((xbt_dict_t *) cfg);
+  this->content = ConfigType<T>::parse(value);
+  this->isdefault = false;
+  this->update();
 }
 
-/** @brief Dump a config set for debuging purpose
- *
- * @param name The name to give to this config set
- * @param indent what to write at the beginning of each line (right number of spaces)
- * @param cfg the config set
- */
-void xbt_cfg_dump(const char *name, const char *indent, xbt_cfg_t cfg)
+template<class T>
+const char* TypedConfigurationElement<T>::getTypeName() // override
 {
-  xbt_dict_t dict = (xbt_dict_t) cfg;
-  xbt_dict_cursor_t cursor = NULL;
-  xbt_cfgelm_t variable = NULL;
-  char *key = NULL;
-  int i;
-  int size;
-  int ival;
-  char *sval;
-  double dval;
+  return ConfigType<T>::type_name;
+}
 
-  if (name)
-    printf("%s>> Dumping of the config set '%s':\n", indent, name);
+} // end of anonymous namespace
 
-  xbt_dict_foreach(dict, cursor, key, variable) {
-    printf("%s  %s:", indent, key);
+// **** Config ****
 
-    size = xbt_dynar_length(variable->content);
-    printf ("%s. Actual size=%d. postset=%p\n",
-            xbt_cfgelm_type_name[variable->type], size, variable->cb_set);
+class Config {
+private:
+  // name -> ConfigElement:
+  std::map<std::string, simgrid::config::ConfigurationElement*> options;
+  // alias -> xbt_dict_elm_t from options:
+  std::map<std::string, simgrid::config::ConfigurationElement*> aliases;
+  bool warn_for_aliases = true;
 
-    switch (variable->type) {
-    case xbt_cfgelm_int:
-      for (i = 0; i < size; i++) {
-        ival = xbt_dynar_get_as(variable->content, i, int);
-        printf("%s    %d\n", indent, ival);
-      }
-      break;
-    case xbt_cfgelm_double:
-      for (i = 0; i < size; i++) {
-        dval = xbt_dynar_get_as(variable->content, i, double);
-        printf("%s    %f\n", indent, dval);
-      }
-      break;
-    case xbt_cfgelm_string:
-      for (i = 0; i < size; i++) {
-        sval = xbt_dynar_get_as(variable->content, i, char *);
-        printf("%s    %s\n", indent, sval);
-      }
-      break;
-    case xbt_cfgelm_boolean:
-      for (i = 0; i < size; i++) {
-        ival = xbt_dynar_get_as(variable->content, i, int);
-        printf("%s    %d\n", indent, ival);
-      }
-      break;
-    case xbt_cfgelm_alias:
-      /* no content */
-      break;
-    default:
-      printf("%s    Invalid type!!\n", indent);
-      break;
-    }
+public:
+  Config() = default;
+  ~Config();
+
+  // No copy:
+  Config(Config const&) = delete;
+  Config& operator=(Config const&) = delete;
+
+  ConfigurationElement& operator[](const char* name);
+  template<class T>
+  TypedConfigurationElement<T>& getTyped(const char* name);
+  void alias(const char* realname, const char* aliasname);
+
+  template<class T, class... A>
+  simgrid::config::TypedConfigurationElement<T>*
+    registerOption(const char* name, A&&... a)
+  {
+    xbt_assert(options.find(name) == options.end(), "Refusing to register the config element '%s' twice.", name);
+    TypedConfigurationElement<T>* variable = new TypedConfigurationElement<T>(name, std::forward<A>(a)...);
+    XBT_DEBUG("Register cfg elm %s (%s) of type %s @%p in set %p)", name, variable->getDescription().c_str(),
+              variable->getTypeName(), variable, this);
+    options.insert({name, variable});
+    variable->update();
+    return variable;
   }
 
-  if (name)
-    printf("%s<< End of the config set '%s'\n", indent, name);
-  fflush(stdout);
+  // Debug:
+  void dump(const char *name, const char *indent);
+  void showAliases();
+  void help();
 
-  xbt_dict_cursor_free(&cursor);
-}
+protected:
+  ConfigurationElement* getDictElement(const char* name);
+};
 
-/*
- * free an config element
- */
-void xbt_cfgelm_free(void *data)
+Config::~Config()
 {
-  xbt_cfgelm_t c = (xbt_cfgelm_t) data;
-
-  XBT_DEBUG("Frees cfgelm %p", c);
-  if (!c)
-    return;
-  if (c->cb_set_free)
-    c->cb_set_free(c->cb_set_data);
-  xbt_free(c->desc);
-  if (c->type != xbt_cfgelm_alias)
-    xbt_dynar_free(&(c->content));
-  free(c);
+  XBT_DEBUG("Frees cfg set %p", this);
+  for (auto const& elm : options)
+    delete elm.second;
 }
 
-/*----[ Registering stuff ]-----------------------------------------------*/
-/** @brief Register an element within a config set
- *
- *  @param cfg the config set
- *  @param name the name of the config element
- *  @param desc a description for this item (used by xbt_cfg_help())
- *  @param type the type of the config element
- *  @param cb_set callback function called when a value is set
- */
-static void xbt_cfg_register(
-  xbt_cfg_t * cfg, const char *name, const char *desc, e_xbt_cfgelm_type_t type,
-  xbt_cfg_cb_t cb_set,
-  xbt_cfg_cb_ext_t cb_set_ext, void* cb_set_data, xbt_cfg_cb_free_t cb_set_free)
-{
-  if (*cfg == NULL)
-    *cfg = xbt_cfg_new();
-  xbt_assert(type >= xbt_cfgelm_int && type <= xbt_cfgelm_boolean,
-              "type of %s not valid (%d should be between %d and %d)",
-             name, (int)type, xbt_cfgelm_int, xbt_cfgelm_boolean);
-
-  xbt_cfgelm_t res = (xbt_cfgelm_t) xbt_dict_get_or_null((xbt_dict_t) * cfg, name);
-  xbt_assert(NULL == res, "Refusing to register the config element '%s' twice.", name);
-
-  res = xbt_new(s_xbt_cfgelm_t, 1);
-  XBT_DEBUG("Register cfg elm %s (%s) (%s (=%d) @%p in set %p)",
-            name, desc, xbt_cfgelm_type_name[type], (int)type, res, *cfg);
-
-  res->desc = xbt_strdup(desc);
-  res->type = type;
-  res->cb_set = cb_set;
-  res->cb_set_ext = cb_set_ext;
-  res->cb_set_data = cb_set_data;
-  res->cb_set_free = cb_set_free;
-  res->isdefault = 1;
-
-  switch (type) {
-  case xbt_cfgelm_int:
-    res->content = xbt_dynar_new(sizeof(int), NULL);
-    break;
-  case xbt_cfgelm_double:
-    res->content = xbt_dynar_new(sizeof(double), NULL);
-    break;
-  case xbt_cfgelm_string:
-    res->content = xbt_dynar_new(sizeof(char *), xbt_free_ref);
-    break;
-  case xbt_cfgelm_boolean:
-    res->content = xbt_dynar_new(sizeof(int), NULL);
-    break;
-  default:
-    XBT_ERROR("%d is an invalid type code", (int)type);
-    break;
-  }
-  xbt_dict_set((xbt_dict_t) * cfg, name, res, NULL);
-}
-
-
-
-void xbt_cfg_register_double(const char *name, double default_value,xbt_cfg_cb_t cb_set, const char *desc){
-  xbt_cfg_register(&simgrid_config,name,desc,xbt_cfgelm_double,cb_set, NULL, NULL, NULL);
-  xbt_cfg_setdefault_double(name, default_value);
-}
-void xbt_cfg_register_int(const char *name, int default_value,xbt_cfg_cb_t cb_set, const char *desc) {
-  xbt_cfg_register(&simgrid_config,name,desc,xbt_cfgelm_int,cb_set, NULL, NULL, NULL);
-  xbt_cfg_setdefault_int(name, default_value);
-}
-void xbt_cfg_register_string(const char *name, const char *default_value, xbt_cfg_cb_t cb_set, const char *desc){
-  xbt_cfg_register(&simgrid_config,name,desc,xbt_cfgelm_string,cb_set, NULL, NULL, NULL);
-  xbt_cfg_setdefault_string(name, default_value);
-}
-void xbt_cfg_register_boolean(const char *name, const char*default_value,xbt_cfg_cb_t cb_set, const char *desc){
-  xbt_cfg_register(&simgrid_config,name,desc,xbt_cfgelm_boolean,cb_set, NULL, NULL, NULL);
-  xbt_cfg_setdefault_boolean(name, default_value);
-}
-
-/** Register a config with an extended callback
- *
- *  @param name      Name of the flag
- *  @param desc      Description of the flag
- *  @param type      Type of the flag
- *  @param cb        Extended callback
- *  @param data      Data associated with the callback
- *  @param data_free Function used to free the callback data (or NULL)
- */
-void xbt_cfg_register_ext(const char *name, const char *desc, e_xbt_cfgelm_type_t type,
-  xbt_cfg_cb_ext_t cb, void* data, xbt_cfg_cb_free_t data_free)
+inline ConfigurationElement* Config::getDictElement(const char* name)
 {
-  xbt_cfg_register(&simgrid_config, name, desc, type, NULL, cb, data, data_free);
+  auto opt = options.find(name);
+  if (opt != options.end()) {
+    return opt->second;
+  } else {
+    auto als = aliases.find(name);
+    if (als != aliases.end()) {
+      ConfigurationElement* res = als->second;
+      if (warn_for_aliases)
+        XBT_INFO("Option %s has been renamed to %s. Consider switching.", name, res->getKey().c_str());
+      return res;
+    } else {
+      throw simgrid::config::missing_key_error(std::string("Bad config key: ") + name);
+    }
+  }
 }
 
-void xbt_cfg_register_alias(const char *newname, const char *oldname)
+inline ConfigurationElement& Config::operator[](const char* name)
 {
-  if (simgrid_config == NULL)
-    simgrid_config = xbt_cfg_new();
-
-  xbt_cfgelm_t res = (xbt_cfgelm_t) xbt_dict_get_or_null((xbt_dict_t) simgrid_config, oldname);
-  xbt_assert(NULL == res, "Refusing to register the option '%s' twice.", oldname);
-
-  res = (xbt_cfgelm_t) xbt_dict_get_or_null((xbt_dict_t) simgrid_config, newname);
-  xbt_assert(res, "Cannot define an alias to the non-existing option '%s'.", newname);
-
-  res = xbt_new0(s_xbt_cfgelm_t, 1);
-  XBT_DEBUG("Register cfg alias %s -> %s)",oldname,newname);
-
-  res->desc = bprintf("Deprecated alias for %s",newname);
-  res->type = xbt_cfgelm_alias;
-  res->isdefault = 1;
-  res->content = (xbt_dynar_t)newname;
+  return *(getDictElement(name));
+}
 
-  xbt_dict_set((xbt_dict_t) simgrid_config, oldname, res, NULL);
+void Config::alias(const char* realname, const char* aliasname)
+{
+  xbt_assert(aliases.find(aliasname) == aliases.end(), "Alias '%s' already.", aliasname);
+  ConfigurationElement* element = this->getDictElement(realname);
+  xbt_assert(element, "Cannot define an alias to the non-existing option '%s'.", realname);
+  this->aliases.insert({aliasname, element});
 }
 
-/**
- * @brief Parse a string and register the stuff described.
- *
- * @param cfg the config set
- * @param entry a string describing the element to register
- *
- * The string may consist in several variable descriptions separated by a space.
- * Each of them must use the following syntax: \<name\>:\<type\>
- * with type being one of  'string','int','bool' or 'double'.
+/** @brief Dump a config set for debuging purpose
  *
- * Note that this does not allow to set the description, so you should prefer the other interface
+ * @param name The name to give to this config set
+ * @param indent what to write at the beginning of each line (right number of spaces)
  */
-void xbt_cfg_register_str(xbt_cfg_t * cfg, const char *entry)
+void Config::dump(const char *name, const char *indent)
 {
-  char *entrycpy = xbt_strdup(entry);
-  char *tok;
-
-  e_xbt_cfgelm_type_t type;
-  XBT_DEBUG("Register string '%s'", entry);
-
-  tok = strchr(entrycpy, ':');
-  xbt_assert(tok, "Invalid config element descriptor: %s; Should be <name>:<type>", entry);
-  *(tok++) = '\0';
-
-  for (type = (e_xbt_cfgelm_type_t)0; type < xbt_cfgelm_type_count && strcmp(tok, xbt_cfgelm_type_name[type]); increment(type));
-  xbt_assert(type < xbt_cfgelm_type_count,
-      "Invalid type in config element descriptor: %s; Should be one of 'string', 'int' or 'double'.", entry);
+  if (name)
+    printf("%s>> Dumping of the config set '%s':\n", indent, name);
 
-  xbt_cfg_register(cfg, entrycpy, NULL, type, NULL, NULL, NULL, NULL);
+  for (auto const& elm : options)
+    printf("%s  %s: ()%s) %s", indent, elm.first.c_str(), elm.second->getTypeName(),
+           elm.second->getStringValue().c_str());
 
-  free(entrycpy);               /* strdup'ed by dict mechanism, but cannot be const */
+  if (name)
+    printf("%s<< End of the config set '%s'\n", indent, name);
+  fflush(stdout);
 }
 
 /** @brief Displays the declared aliases and their description */
-void xbt_cfg_aliases(void)
+void Config::showAliases()
 {
-  xbt_dict_cursor_t dict_cursor;
-  unsigned int dynar_cursor;
-  xbt_cfgelm_t variable;
-  char *name;
-  xbt_dynar_t names = xbt_dynar_new(sizeof(char *), NULL);
-
-  xbt_dict_foreach((xbt_dict_t )simgrid_config, dict_cursor, name, variable)
-    xbt_dynar_push(names, &name);
-  xbt_dynar_sort_strings(names);
-
-  xbt_dynar_foreach(names, dynar_cursor, name) {
-    variable = (xbt_cfgelm_t) xbt_dict_get((xbt_dict_t )simgrid_config, name);
+  bool old_warn_for_aliases = false;
+  std::swap(warn_for_aliases, old_warn_for_aliases);
+  for (auto const& elm : aliases)
+    printf("   %s: %s\n", elm.first.c_str(), (*this)[elm.first.c_str()].getDescription().c_str());
+  std::swap(warn_for_aliases, old_warn_for_aliases);
+}
 
-    if (variable->type == xbt_cfgelm_alias)
-      printf("   %s: %s\n", name, variable->desc);
+/** @brief Displays the declared options and their description */
+void Config::help()
+{
+  for (auto const& elm : options) {
+    simgrid::config::ConfigurationElement* variable = this->options.at(elm.first);
+    printf("   %s: %s\n", elm.first.c_str(), variable->getDescription().c_str());
+    printf("       Type: %s; ", variable->getTypeName());
+    printf("Current value: %s\n", variable->getStringValue().c_str());
   }
 }
 
-/** @brief Displays the declared options and their description */
-void xbt_cfg_help(void)
-{
-  xbt_dict_cursor_t dict_cursor;
-  unsigned int dynar_cursor;
-  xbt_cfgelm_t variable;
-  char *name;
-  xbt_dynar_t names = xbt_dynar_new(sizeof(char *), NULL);
-
-  xbt_dict_foreach((xbt_dict_t )simgrid_config, dict_cursor, name, variable)
-    xbt_dynar_push(names, &name);
-  xbt_dynar_sort_strings(names);
-
-  xbt_dynar_foreach(names, dynar_cursor, name) {
-    int size;
-    variable = (xbt_cfgelm_t) xbt_dict_get((xbt_dict_t )simgrid_config, name);
-    if (variable->type == xbt_cfgelm_alias)
-      continue;
+// ***** getConfig *****
 
-    printf("   %s: %s\n", name, variable->desc);
-    printf("       Type: %s; ", xbt_cfgelm_type_name[variable->type]);
-    size = xbt_dynar_length(variable->content);
-    printf("Current value: ");
-
-    if (size != 1)
-      printf(size == 0 ? "n/a\n" : "{ ");
-    for (int i = 0; i < size; i++) {
-      const char *sep = (size == 1 ? "\n" : (i < size - 1 ? ", " : " }\n"));
-
-      switch (variable->type) {
-      case xbt_cfgelm_int:
-        printf("%d%s", xbt_dynar_get_as(variable->content, i, int), sep);
-        break;
-      case xbt_cfgelm_double:
-        printf("%f%s", xbt_dynar_get_as(variable->content, i, double), sep);
-        break;
-      case xbt_cfgelm_string:
-        printf("'%s'%s", xbt_dynar_get_as(variable->content, i, char *), sep);
-        break;
-      case xbt_cfgelm_boolean: {
-        int b = xbt_dynar_get_as(variable->content, i, int);
-        const char *bs = b ? xbt_cfgelm_boolean_values[0].true_val: xbt_cfgelm_boolean_values[0].false_val;
-        if (b == 0 || b == 1)
-          printf("'%s'%s", bs, sep);
-        else
-          printf("'%s/%d'%s", bs, b, sep);
-        break;
-      }
-      default:
-        printf("Invalid type!!%s", sep);
-        break;
-      }
-    }
-  }
-  xbt_dynar_free(&names);
+template<class T>
+XBT_PUBLIC(T const&) getConfig(const char* name)
+{
+  return (*simgrid_config)[name].getValue<T>();
 }
 
-static xbt_cfgelm_t xbt_cfgelm_get(xbt_cfg_t cfg, const char *name, e_xbt_cfgelm_type_t type)
+template XBT_PUBLIC(int const&) getConfig<int>(const char* name);
+template XBT_PUBLIC(double const&) getConfig<double>(const char* name);
+template XBT_PUBLIC(bool const&) getConfig<bool>(const char* name);
+template XBT_PUBLIC(std::string const&) getConfig<std::string>(const char* name);
+
+// ***** alias *****
+
+void alias(const char* realname, const char* aliasname)
 {
-  xbt_cfgelm_t res = (xbt_cfgelm_t) xbt_dict_get_or_null((xbt_dict_t) cfg, name);
+  simgrid_config->alias(realname, aliasname);
+}
 
-  // The user used the old name. Switch to the new one after a short warning
-  while (res && res->type == xbt_cfgelm_alias) {
-    const char* newname = (const char *)res->content;
-    XBT_INFO("Option %s has been renamed to %s. Consider switching.", name, newname);
-    res = xbt_cfgelm_get(cfg, newname, type);
-  }
+// ***** declareFlag *****
 
-  if (!res) {
-    xbt_cfg_help();
-    fflush(stdout);
-    THROWF(not_found_error, 0, "No registered variable '%s' in this config set.", name);
+template<class T>
+XBT_PUBLIC(void) declareFlag(const char* name, const char* description,
+  T value, std::function<void(const T&)> callback)
+{
+  if (simgrid_config == nullptr) {
+    simgrid_config = xbt_cfg_new();
+    atexit(sg_config_finalize);
   }
+  simgrid_config->registerOption<T>(
+    name, description, std::move(value), std::move(callback));
+}
 
-  xbt_assert(type == xbt_cfgelm_any || res->type == type,
-              "You tried to access to the config element %s as an %s, but its type is %s.",
-              name, xbt_cfgelm_type_name[type], xbt_cfgelm_type_name[res->type]);
-  return res;
+template XBT_PUBLIC(void) declareFlag(const char* name,
+  const char* description, int value, std::function<void(int const &)> callback);
+template XBT_PUBLIC(void) declareFlag(const char* name,
+  const char* description, double value, std::function<void(double const &)> callback);
+template XBT_PUBLIC(void) declareFlag(const char* name,
+  const char* description, bool value, std::function<void(bool const &)> callback);
+template XBT_PUBLIC(void) declareFlag(const char* name,
+  const char* description, std::string value, std::function<void(std::string const &)> callback);
+
+}
 }
 
-/** @brief Get the type of this variable in that configuration set
- *
- * @param cfg the config set
- * @param name the name of the element
- *
- * @return the type of the given element
- */
-e_xbt_cfgelm_type_t xbt_cfg_get_type(xbt_cfg_t cfg, const char *name)
-{
-  xbt_cfgelm_t variable = NULL;
+// ***** C bindings *****
 
-  variable = (xbt_cfgelm_t) xbt_dict_get_or_null((xbt_dict_t) cfg, name);
-  if (!variable)
-    THROWF(not_found_error, 0, "Can't get the type of '%s' since this variable does not exist", name);
+xbt_cfg_t xbt_cfg_new()        { return new simgrid::config::Config(); }
+void xbt_cfg_free(xbt_cfg_t * cfg) { delete *cfg; }
 
-  XBT_DEBUG("type in variable = %d", (int)variable->type);
-  return variable->type;
+void xbt_cfg_dump(const char *name, const char *indent, xbt_cfg_t cfg)
+{
+  cfg->dump(name, indent);
 }
 
-/*----[ Setting ]---------------------------------------------------------*/
-/**  @brief va_args version of xbt_cfg_set
- *
- * @param cfg config set to fill
- * @param name  variable name
- * @param pa  variable value
- *
- * Add some values to the config set.
- */
-void xbt_cfg_set_vargs(xbt_cfg_t cfg, const char *name, va_list pa)
+/*----[ Registering stuff ]-----------------------------------------------*/
+
+void xbt_cfg_register_double(const char *name, double default_value,
+  xbt_cfg_cb_t cb_set, const char *desc)
 {
-  char *str;
-  int i;
-  double d;
-  e_xbt_cfgelm_type_t type = xbt_cfgelm_type_count; /* Set a dummy value to make gcc happy. It cannot get uninitialized */
+  if (simgrid_config == nullptr)
+    simgrid_config = xbt_cfg_new();
+  simgrid_config->registerOption<double>(name, desc, default_value, cb_set);
+}
 
-  xbt_ex_t e;
+void xbt_cfg_register_int(const char *name, int default_value,xbt_cfg_cb_t cb_set, const char *desc)
+{
+  if (simgrid_config == nullptr) {
+    simgrid_config = xbt_cfg_new();
+    atexit(&sg_config_finalize);
+  }
+  simgrid_config->registerOption<int>(name, desc, default_value, cb_set);
+}
 
-  TRY {
-    type = xbt_cfg_get_type(cfg, name);
+void xbt_cfg_register_string(const char *name, const char *default_value, xbt_cfg_cb_t cb_set, const char *desc)
+{
+  if (simgrid_config == nullptr) {
+    simgrid_config = xbt_cfg_new();
+    atexit(sg_config_finalize);
   }
-  CATCH(e) {
-    if (e.category == not_found_error) {
-      xbt_ex_free(e);
-      THROWF(not_found_error, 0, "Can't set the property '%s' since it's not registered", name);
-    }
-    RETHROW;
-  }
-
-  switch (type) {
-  case xbt_cfgelm_string:
-    str = va_arg(pa, char *);
-    xbt_cfg_set_string(name, str);
-    break;
-  case xbt_cfgelm_int:
-    i = va_arg(pa, int);
-    xbt_cfg_set_int(name, i);
-    break;
-  case xbt_cfgelm_double:
-    d = va_arg(pa, double);
-    xbt_cfg_set_double(name, d);
-    break;
-  case xbt_cfgelm_boolean:
-    str = va_arg(pa, char *);
-    xbt_cfg_set_boolean(name, str);
-    break;
-  default:
-    xbt_die("Config element variable %s not valid (type=%d)", name, (int)type);
-  }
-}
-
-/** @brief Add a NULL-terminated list of pairs {(char*)key, value} to the set
- *
- * @param cfg config set to fill
- * @param name variable name
- * @param ... variable value
- */
-void xbt_cfg_set(xbt_cfg_t cfg, const char *name, ...)
+  simgrid_config->registerOption<std::string>(name, desc,
+    default_value ? default_value : "", cb_set);
+}
+
+void xbt_cfg_register_boolean(const char *name, const char*default_value,xbt_cfg_cb_t cb_set, const char *desc)
 {
-  va_list pa;
+  if (simgrid_config == nullptr) {
+    simgrid_config = xbt_cfg_new();
+    atexit(sg_config_finalize);
+  }
+  simgrid_config->registerOption<bool>(name, desc, simgrid::config::parseBool(default_value), cb_set);
+}
 
-  va_start(pa, name);
-  xbt_cfg_set_vargs(cfg, name, pa);
-  va_end(pa);
+void xbt_cfg_register_alias(const char *realname, const char *aliasname)
+{
+  if (simgrid_config == nullptr) {
+    simgrid_config = xbt_cfg_new();
+    atexit(sg_config_finalize);
+  }
+  simgrid_config->alias(realname, aliasname);
 }
 
+void xbt_cfg_aliases() { simgrid_config->showAliases(); }
+void xbt_cfg_help()    { simgrid_config->help(); }
+
+/*----[ Setting ]---------------------------------------------------------*/
+
 /** @brief Add values parsed from a string into a config set
  *
  * @param options a string containing the content to add to the config set. This is a '\\t',' ' or '\\n' or ','
@@ -516,7 +492,7 @@ void xbt_cfg_set(xbt_cfg_t cfg, const char *name, ...)
  */
 void xbt_cfg_set_parse(const char *options)
 {
-  if (!options || !strlen(options)) {   /* nothing to do */
+  if (not options || not strlen(options)) { /* nothing to do */
     return;
   }
   char *optionlist_cpy = xbt_strdup(options);
@@ -524,7 +500,7 @@ void xbt_cfg_set_parse(const char *options)
   XBT_DEBUG("List to parse and set:'%s'", options);
   char *option = optionlist_cpy;
   while (1) {                   /* breaks in the code */
-    if (!option)
+    if (not option)
       break;
     char *name = option;
     int len = strlen(name);
@@ -537,7 +513,7 @@ void xbt_cfg_set_parse(const char *options)
     }
     if (option - name == len) {
       XBT_DEBUG("Boundary=EOL");
-      option = NULL;            /* don't do next iteration */
+      option = nullptr;            /* don't do next iteration */
     } else {
       XBT_DEBUG("Boundary on '%c'. len=%d;option-name=%ld", *option, len, (long) (option - name));
       /* Pass the following blank chars */
@@ -547,13 +523,13 @@ void xbt_cfg_set_parse(const char *options)
         option++;
       }
       if (option - name == len - 1)
-        option = NULL;          /* don't do next iteration */
+        option = nullptr;          /* don't do next iteration */
     }
     XBT_DEBUG("parse now:'%s'; parse later:'%s'", name, option);
 
     if (name[0] == ' ' || name[0] == '\n' || name[0] == '\t')
       continue;
-    if (!strlen(name))
+    if (not strlen(name))
       break;
 
     char *val = strchr(name, ':');
@@ -561,80 +537,52 @@ void xbt_cfg_set_parse(const char *options)
     /* don't free(optionlist_cpy) if the assert fails, 'name' points inside it */
     *(val++) = '\0';
 
-    if (strncmp(name, "contexts/", strlen("contexts/")) && strncmp(name, "path", strlen("path")))
+    if (strncmp(name, "path", strlen("path")))
       XBT_INFO("Configuration change: Set '%s' to '%s'", name, val);
 
-    TRY {
-      xbt_cfg_set_as_string(name,val);
-    } CATCH_ANONYMOUS {
-      free(optionlist_cpy);
-      RETHROW;
+    try {
+      (*simgrid_config)[name].setStringValue(val);
+    }
+    catch (simgrid::config::missing_key_error& e) {
+      goto on_missing_key;
+    }
+    catch (...) {
+      goto on_exception;
     }
   }
+
+  free(optionlist_cpy);
+  return;
+
+  /* Do not THROWF from a C++ exception catching context, or some cleanups will be missing */
+on_missing_key:
+  free(optionlist_cpy);
+  THROWF(not_found_error, 0, "Could not set variables %s", options);
+  return;
+on_exception:
   free(optionlist_cpy);
+  THROWF(unknown_error, 0, "Could not set variables %s", options);
 }
 
+// Horrible mess to translate C++ exceptions to C exceptions:
+// Exit from the catch block (and do the correct exception cleaning) before attempting to THROWF.
+#define TRANSLATE_EXCEPTIONS(...) \
+  catch(simgrid::config::missing_key_error& e) { THROWF(not_found_error, 0, __VA_ARGS__); abort(); } \
+  catch(...) { THROWF(not_found_error, 0, __VA_ARGS__); abort(); }
+
 /** @brief Set the value of a variable, using the string representation of that value
  *
  * @param key name of the variable to modify
  * @param value string representation of the value to set
- *
- * @return the first char after the parsed value in val
  */
 
-void *xbt_cfg_set_as_string(const char *key, const char *value) {
-  xbt_ex_t e;
-
-  char *ret;
-  volatile xbt_cfgelm_t variable = NULL;
-  int i;
-  double d;
-
-  TRY {
-    while (variable == NULL) {
-      variable = (xbt_cfgelm_t) xbt_dict_get((xbt_dict_t) simgrid_config, key);
-      if (variable->type == xbt_cfgelm_alias) {
-        const char *newname = (const char*)variable->content;
-        XBT_INFO("Note: configuration '%s' is deprecated. Please use '%s' instead.", key, newname);
-        key = newname;
-        variable = NULL;
-      }
-    }
-  } CATCH(e) {
-    if (e.category == not_found_error) {
-      xbt_ex_free(e);
-      THROWF(not_found_error, 0, "No registered variable corresponding to '%s'.", key);
-    }
-    RETHROW;
-  }
-
-  switch (variable->type) {
-  case xbt_cfgelm_string:
-    xbt_cfg_set_string(key, value);     /* throws */
-    break;
-  case xbt_cfgelm_int:
-    i = strtol(value, &ret, 0);
-    if (ret == value) {
-      xbt_die("Value of option %s not valid. Should be an integer", key);
-    }
-    xbt_cfg_set_int(key, i);  /* throws */
-    break;
-  case xbt_cfgelm_double:
-    d = strtod(value, &ret);
-    if (ret == value) {
-      xbt_die("Value of option %s not valid. Should be a double", key);
-    }
-    xbt_cfg_set_double(key, d);       /* throws */
-    break;
-  case xbt_cfgelm_boolean:
-    xbt_cfg_set_boolean(key, value);  /* throws */
-    ret = (char *)value + strlen(value);
-    break;
-  default:
-    THROWF(unknown_error, 0, "Type of config element %s is not valid.", key);
-    break;
+void xbt_cfg_set_as_string(const char *key, const char *value)
+{
+  try {
+    (*simgrid_config)[key].setStringValue(value);
+    return;
   }
-  return ret;
+  TRANSLATE_EXCEPTIONS("Could not set variable %s as string %s", key, value);
 }
 
 /** @brief Set an integer value to \a name within \a cfg if it wasn't changed yet
@@ -642,15 +590,13 @@ void *xbt_cfg_set_as_string(const char *key, const char *value) {
  * This is useful to change the default value of a variable while allowing
  * users to override it with command line arguments
  */
-void xbt_cfg_setdefault_int(const char *name, int val)
+void xbt_cfg_setdefault_int(const char *key, int value)
 {
-  xbt_cfgelm_t variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_int);
-
-  if (variable->isdefault){
-    xbt_cfg_set_int(name, val);
-    variable->isdefault = 1;
-  } else
-    XBT_DEBUG("Do not override configuration variable '%s' with value '%d' because it was already set.", name, val);
+  try {
+    (*simgrid_config)[key].setDefaultValue<int>(value);
+    return;
+  }
+  TRANSLATE_EXCEPTIONS("Could not set variable %s to default integer %i", key, value);
 }
 
 /** @brief Set an integer value to \a name within \a cfg if it wasn't changed yet
@@ -658,15 +604,13 @@ void xbt_cfg_setdefault_int(const char *name, int val)
  * This is useful to change the default value of a variable while allowing
  * users to override it with command line arguments
  */
-void xbt_cfg_setdefault_double(const char *name, double val)
+void xbt_cfg_setdefault_double(const char *key, double value)
 {
-  xbt_cfgelm_t variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_double);
-
-  if (variable->isdefault) {
-    xbt_cfg_set_double(name, val);
-    variable->isdefault = 1;
-  } else
-    XBT_DEBUG("Do not override configuration variable '%s' with value '%f' because it was already set.", name, val);
+  try {
+    (*simgrid_config)[key].setDefaultValue<double>(value);
+    return;
+  }
+  TRANSLATE_EXCEPTIONS("Could not set variable %s to default double %f", key, value);
 }
 
 /** @brief Set a string value to \a name within \a cfg if it wasn't changed yet
@@ -674,15 +618,13 @@ void xbt_cfg_setdefault_double(const char *name, double val)
  * This is useful to change the default value of a variable while allowing
  * users to override it with command line arguments
  */
-void xbt_cfg_setdefault_string(const char *name, const char *val)
+void xbt_cfg_setdefault_string(const char *key, const char *value)
 {
-  xbt_cfgelm_t variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_string);
-
-  if (variable->isdefault){
-    xbt_cfg_set_string(name, val);
-    variable->isdefault = 1;
-  } else
-    XBT_DEBUG("Do not override configuration variable '%s' with value '%s' because it was already set.", name, val);
+  try {
+    (*simgrid_config)[key].setDefaultValue<std::string>(value ? value : "");
+    return;
+  }
+  TRANSLATE_EXCEPTIONS("Could not set variable %s to default string %s", key, value);
 }
 
 /** @brief Set an boolean value to \a name within \a cfg if it wasn't changed yet
@@ -690,285 +632,227 @@ void xbt_cfg_setdefault_string(const char *name, const char *val)
  * This is useful to change the default value of a variable while allowing
  * users to override it with command line arguments
  */
-void xbt_cfg_setdefault_boolean(const char *name, const char *val)
+void xbt_cfg_setdefault_boolean(const char *key, const char *value)
 {
-  xbt_cfgelm_t variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_boolean);
-
-  if (variable->isdefault){
-    xbt_cfg_set_boolean(name, val);
-    variable->isdefault = 1;
+  try {
+    (*simgrid_config)[key].setDefaultValue<bool>(simgrid::config::parseBool(value));
+    return;
   }
-   else
-    XBT_DEBUG("Do not override configuration variable '%s' with value '%s' because it was already set.", name, val);
+  TRANSLATE_EXCEPTIONS("Could not set variable %s to default boolean %s", key, value);
 }
 
 /** @brief Set an integer value to \a name within \a cfg
  *
- * @param name the name of the variable
- * @param val the value of the variable
+ * @param key the name of the variable
+ * @param value the value of the variable
  */
-void xbt_cfg_set_int(const char *name, int val)
+void xbt_cfg_set_int(const char *key, int value)
 {
-  xbt_cfgelm_t variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_int);
-
-  xbt_dynar_set(variable->content, 0, &val);
-
-  if (variable->cb_set)
-    variable->cb_set(name);
-  if (variable->cb_set_ext)
-    variable->cb_set_ext(name, variable->cb_set_data);
-  variable->isdefault = 0;
+  try {
+    (*simgrid_config)[key].setValue<int>(value);
+    return;
+  }
+  TRANSLATE_EXCEPTIONS("Could not set variable %s to integer %i", key, value);
 }
 
 /** @brief Set or add a double value to \a name within \a cfg
  *
- * @param name the name of the variable
- * @param val the double to set
+ * @param key the name of the variable
+ * @param value the double to set
  */
-void xbt_cfg_set_double(const char *name, double val)
+void xbt_cfg_set_double(const char *key, double value)
 {
-  xbt_cfgelm_t variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_double);
-
-  xbt_dynar_set(variable->content, 0, &val);
-
-  if (variable->cb_set)
-    variable->cb_set(name);
-  if (variable->cb_set_ext)
-    variable->cb_set_ext(name, variable->cb_set_data);
-  variable->isdefault = 0;
+  try {
+    (*simgrid_config)[key].setValue<double>(value);
+    return;
+  }
+  TRANSLATE_EXCEPTIONS("Could not set variable %s to double %f", key, value);
 }
 
 /** @brief Set or add a string value to \a name within \a cfg
  *
- * @param cfg the config set
- * @param name the name of the variable
- * @param val the value to be added
+ * @param key the name of the variable
+ * @param value the value to be added
  *
  */
-void xbt_cfg_set_string(const char *name, const char *val)
+void xbt_cfg_set_string(const char *key, const char *value)
 {
-  char *newval = xbt_strdup(val);
-  xbt_cfgelm_t variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_string);
-
-  if (!xbt_dynar_is_empty(variable->content)) {
-    char *sval = xbt_dynar_get_as(variable->content, 0, char *);
-    free(sval);
+  try {
+    (*simgrid_config)[key].setValue<std::string>(value ? value : "");
+    return;
   }
-
-  xbt_dynar_set(variable->content, 0, &newval);
-
-  if (variable->cb_set)
-    variable->cb_set(name);
-  if (variable->cb_set_ext)
-    variable->cb_set_ext(name, variable->cb_set_data);
-  variable->isdefault = 0;
+  TRANSLATE_EXCEPTIONS("Could not set variable %s to string %s", key, value);
 }
 
 /** @brief Set or add a boolean value to \a name within \a cfg
  *
- * @param name the name of the variable
- * @param val the value of the variable
+ * @param key the name of the variable
+ * @param value the value of the variable
  */
-void xbt_cfg_set_boolean(const char *name, const char *val)
+void xbt_cfg_set_boolean(const char *key, const char *value)
 {
-  int bval=-1;
-  xbt_cfgelm_t variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_boolean);
-
-  for (int i = 0; xbt_cfgelm_boolean_values[i].true_val != NULL; i++) {
-    if (strcmp(val, xbt_cfgelm_boolean_values[i].true_val) == 0){
-      bval = 1;
-      break;
-    }
-    if (strcmp(val, xbt_cfgelm_boolean_values[i].false_val) == 0){
-      bval = 0;
-      break;
-    }
+  try {
+    (*simgrid_config)[key].setValue<bool>(simgrid::config::parseBool(value));
+    return;
   }
-  xbt_assert(bval != -1, "Value of option '%s' not valid. Should be a boolean (yes,no,on,off,true,false,0,1)", val);
-  xbt_dynar_set(variable->content, 0, &bval);
-
-  if (variable->cb_set)
-    variable->cb_set(name);
-  if (variable->cb_set_ext)
-    variable->cb_set_ext(name, variable->cb_set_data);
-  variable->isdefault = 0;
+  TRANSLATE_EXCEPTIONS("Could not set variable %s to boolean %s", key, value);
 }
 
 
 /* Say if the value is the default value */
-int xbt_cfg_is_default_value(const char *name)
+int xbt_cfg_is_default_value(const char *key)
 {
-  xbt_cfgelm_t variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_any);
-  return variable->isdefault;
+  try {
+    return (*simgrid_config)[key].isDefault() ? 1 : 0;
+  }
+  TRANSLATE_EXCEPTIONS("Could not get variable %s", key);
 }
 
 /*----[ Getting ]---------------------------------------------------------*/
 /** @brief Retrieve an integer value of a variable (get a warning if not uniq)
  *
- * @param name the name of the variable
+ * @param key the name of the variable
  *
  * Returns the first value from the config set under the given name.
- * If there is more than one value, it will issue a warning. Consider using xbt_cfg_get_dynar() instead.
  */
-int xbt_cfg_get_int(const char *name)
+int xbt_cfg_get_int(const char *key)
 {
-  xbt_cfgelm_t variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_int);
-
-  if (xbt_dynar_length(variable->content) > 1) {
-    XBT_WARN("You asked for the first value of the config element '%s', but there is %lu values",
-         name, xbt_dynar_length(variable->content));
+  try {
+    return (*simgrid_config)[key].getValue<int>();
   }
-
-  return xbt_dynar_get_as(variable->content, 0, int);
+  TRANSLATE_EXCEPTIONS("Could not get variable %s", key);
 }
 
 /** @brief Retrieve a double value of a variable (get a warning if not uniq)
  *
- * @param cfg the config set
- * @param name the name of the variable
+ * @param key the name of the variable
  *
  * Returns the first value from the config set under the given name.
- * If there is more than one value, it will issue a warning. Consider using xbt_cfg_get_dynar() instead.
  */
-double xbt_cfg_get_double(const char *name)
+double xbt_cfg_get_double(const char *key)
 {
-  xbt_cfgelm_t variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_double);
-
-  if (xbt_dynar_length(variable->content) > 1) {
-    XBT_WARN ("You asked for the first value of the config element '%s', but there is %lu values\n",
-         name, xbt_dynar_length(variable->content));
+  try {
+    return (*simgrid_config)[key].getValue<double>();
   }
-
-  return xbt_dynar_get_as(variable->content, 0, double);
+  TRANSLATE_EXCEPTIONS("Could not get variable %s", key);
 }
 
 /** @brief Retrieve a string value of a variable (get a warning if not uniq)
  *
- * @param cfg the config set
- * @param name the name of the variable
+ * @param key the name of the variable
  *
  * Returns the first value from the config set under the given name.
- * If there is more than one value, it will issue a warning. Consider using
- * xbt_cfg_get_dynar() instead. Returns NULL if there is no value.
+ * If there is more than one value, it will issue a warning.
+ * Returns nullptr if there is no value.
  *
  * \warning the returned value is the actual content of the config set
  */
-char *xbt_cfg_get_string(const char *name)
+char *xbt_cfg_get_string(const char *key)
 {
-  xbt_cfgelm_t variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_string);
-
-  if (xbt_dynar_length(variable->content) > 1) {
-    XBT_WARN("You asked for the first value of the config element '%s', but there is %lu values\n",
-         name, xbt_dynar_length(variable->content));
-  } else if (xbt_dynar_is_empty(variable->content)) {
-    return NULL;
+  try {
+    return (char*) (*simgrid_config)[key].getValue<std::string>().c_str();
   }
-
-  return xbt_dynar_get_as(variable->content, 0, char *);
+  TRANSLATE_EXCEPTIONS("Could not get variable %s", key);
 }
 
 /** @brief Retrieve a boolean value of a variable (get a warning if not uniq)
  *
- * @param cfg the config set
- * @param name the name of the variable
+ * @param key the name of the variable
  *
  * Returns the first value from the config set under the given name.
- * If there is more than one value, it will issue a warning. Consider using xbt_cfg_get_dynar() instead.
+ * If there is more than one value, it will issue a warning.
  */
-int xbt_cfg_get_boolean(const char *name)
+int xbt_cfg_get_boolean(const char *key)
 {
-  xbt_cfgelm_t variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_boolean);
-
-  if (xbt_dynar_length(variable->content) > 1) {
-    XBT_WARN("You asked for the first value of the config element '%s', but there is %lu values",
-         name, xbt_dynar_length(variable->content));
+  try {
+    return (*simgrid_config)[key].getValue<bool>() ? 1 : 0;
   }
-
-  return xbt_dynar_get_as(variable->content, 0, int);
-}
-
-namespace simgrid {
-namespace config {
-
-static void callCallback(const char* name, void* data)
-{
-  (*(std::function<void(const char*)>*) data)(name);
+  TRANSLATE_EXCEPTIONS("Could not get variable %s", key);
 }
 
-static void freeCallback(void* data)
-{
-  delete (std::function<void(const char*)>*) data;
-}
-
-void registerConfig(const char* name, const char* description,
-  e_xbt_cfgelm_type_t type,
-  std::function<void(const char*)> callback)
-{
-  std::function<void(const char*)>* code
-    = new std::function<void(const char*)>(std::move(callback));
-  xbt_cfg_register_ext(name, description, type,
-    callCallback, code, freeCallback);
-}
+#ifdef SIMGRID_TEST
 
-}
-}
+#include <string>
 
-#ifdef SIMGRID_TEST
 #include "xbt.h"
 #include "xbt/ex.h"
+#include <xbt/ex.hpp>
+
+#include <xbt/config.hpp>
 
 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(xbt_cfg);
 
 XBT_TEST_SUITE("config", "Configuration support");
 
-static xbt_cfg_t make_set()
-{
-  xbt_cfg_t set = NULL;
+XBT_PUBLIC_DATA(xbt_cfg_t) simgrid_config;
 
+static void make_set()
+{
+  simgrid_config = nullptr;
   xbt_log_threshold_set(&_XBT_LOGV(xbt_cfg), xbt_log_priority_critical);
-  xbt_cfg_register_str(&set, "speed:int");
-  xbt_cfg_register_str(&set, "peername:string");
-  xbt_cfg_register_str(&set, "user:string");
-
-  return set;
+  xbt_cfg_register_int("speed", 0, nullptr, "");
+  xbt_cfg_register_string("peername", "", nullptr, "");
+  xbt_cfg_register_string("user", "", nullptr, "");
 }                               /* end_of_make_set */
 
-XBT_PUBLIC_DATA(xbt_cfg_t) simgrid_config;
-
 XBT_TEST_UNIT("memuse", test_config_memuse, "Alloc and free a config set")
 {
-  simgrid_config = make_set();
+  auto temp = simgrid_config;
+  make_set();
   xbt_test_add("Alloc and free a config set");
   xbt_cfg_set_parse("peername:veloce user:bidule");
   xbt_cfg_free(&simgrid_config);
+  simgrid_config = temp;
 }
 
 XBT_TEST_UNIT("use", test_config_use, "Data retrieving tests")
 {
-  simgrid_config = make_set();
+  auto temp = simgrid_config;
+  make_set();
   xbt_test_add("Get a single value");
   {
     /* get_single_value */
-    int ival;
-
     xbt_cfg_set_parse("peername:toto:42 speed:42");
-    ival = xbt_cfg_get_int("speed");
+    int ival = xbt_cfg_get_int("speed");
     if (ival != 42)
       xbt_test_fail("Speed value = %d, I expected 42", ival);
   }
 
   xbt_test_add("Access to a non-existant entry");
   {
-    xbt_ex_t e;
-
-    TRY {
+    try {
       xbt_cfg_set_parse("color:blue");
-    } CATCH(e) {
+    } catch(xbt_ex& e) {
       if (e.category != not_found_error)
         xbt_test_exception(e);
-      xbt_ex_free(e);
     }
   }
   xbt_cfg_free(&simgrid_config);
+  simgrid_config = temp;
 }
+
+XBT_TEST_UNIT("c++flags", test_config_cxx_flags, "C++ flags")
+{
+  auto temp = simgrid_config;
+  make_set();
+  xbt_test_add("C++ declaration of flags");
+
+  simgrid::config::Flag<int> int_flag("int", "", 0);
+  simgrid::config::Flag<std::string> string_flag("string", "", "foo");
+  simgrid::config::Flag<double> double_flag("double", "", 0.32);
+  simgrid::config::Flag<bool> bool_flag1("bool1", "", false);
+  simgrid::config::Flag<bool> bool_flag2("bool2", "", true);
+
+  xbt_test_add("Parse values");
+  xbt_cfg_set_parse("int:42 string:bar double:8.0 bool1:true bool2:false");
+  xbt_test_assert(int_flag == 42, "Check int flag");
+  xbt_test_assert(string_flag == "bar", "Check string flag");
+  xbt_test_assert(double_flag == 8.0, "Check double flag");
+  xbt_test_assert(bool_flag1, "Check bool1 flag");
+  xbt_test_assert(not bool_flag2, "Check bool2 flag");
+
+  xbt_cfg_free(&simgrid_config);
+  simgrid_config = temp;
+}
+
 #endif                          /* SIMGRID_TEST */