X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/9d446af3d297ad838f88db08fc5706f386362ddc..018ba3d20987082f79c483bc44fcb83cd2425a78:/src/xbt/config.cpp

diff --git a/src/xbt/config.cpp b/src/xbt/config.cpp
index 60a7f5193f..53e31e1b84 100644
--- a/src/xbt/config.cpp
+++ b/src/xbt/config.cpp
@@ -3,7 +3,11 @@
 
 #include <stdio.h>
 
+#include <cerrno>
+#include <cstring>
+#include <climits>
 #include <functional>
+#include <stdexcept>
 #include <string>
 #include <type_traits>
 
@@ -24,7 +28,6 @@ XBT_EXPORT_NO_IMPORT(xbt_cfg_t) simgrid_config = NULL;
 
 namespace {
 
-// We could define some range/iterator for the num values.
 static inline
 void increment(e_xbt_cfgelm_type_t& type)
 {
@@ -34,9 +37,11 @@ void increment(e_xbt_cfgelm_type_t& type)
 
 }
 
-/* xbt_cfgelm_t: the typedef corresponding to a config variable. */
+namespace simgrid {
+namespace config {
 
-typedef struct s_xbt_cfgelm_t {
+// A configuration variable:
+struct ConfigurationElement {
   /* Description */
   std::string desc;
 
@@ -44,29 +49,68 @@ typedef struct s_xbt_cfgelm_t {
   e_xbt_cfgelm_type_t type;
   bool isdefault = true;
 
-  /* Callbacks */
+  /* Callback */
   xbt_cfg_cb_t cb_set = nullptr;
 
-  /* Advanced callbacks */
-  xbt_cfg_cb_ext_t cb_set_ext = nullptr;
-  void* cb_set_data = nullptr;
-  xbt_cfg_cb_free_t cb_set_free = nullptr;
+  /* Advanced callback (for xbt_cfgelm_string only) */
+  std::function<void(const char* value)> callback;
 
-  /* actual content (could be an union or something) */
-  xbt_dynar_t content = nullptr;
+  union {
+    int int_content;
+    double double_content;
+    char* string_content;
+    bool boolean_content;
+  };
 
-  ~s_xbt_cfgelm_t()
+  ~ConfigurationElement()
   {
     XBT_DEBUG("Frees cfgelm %p", this);
-    if (!this)
-      return;
-    if (this->cb_set_free)
-      this->cb_set_free(this->cb_set_data);
-    if (this->type != xbt_cfgelm_alias)
-      xbt_dynar_free(&(this->content));
+    switch(this->type) {
+    case xbt_cfgelm_int:
+    case xbt_cfgelm_double:
+    case xbt_cfgelm_boolean:
+      break;
+    case xbt_cfgelm_string:
+    case xbt_cfgelm_alias:
+      free(string_content);
+      break;
+    default:
+      xbt_die("Unexpected config type");
+    }
   }
 
-} s_xbt_cfgelm_t, *xbt_cfgelm_t;
+};
+
+struct Config {
+  xbt_dict_t options;
+
+  Config();
+  ~Config();
+
+  // No copy:
+  Config(Config const&) = delete;
+  Config& operator=(Config const&) = delete;
+};
+
+/* Internal stuff used in cache to free a variable */
+static void xbt_cfgelm_free(void *data)
+{
+  if (data)
+    delete (simgrid::config::ConfigurationElement*) data;
+}
+
+Config::Config() :
+  options(xbt_dict_new_homogeneous(xbt_cfgelm_free))
+{}
+
+Config::~Config()
+{
+  XBT_DEBUG("Frees cfg set %p", this);
+  xbt_dict_free(&this->options);
+}
+
+}
+}
 
 static const char *xbt_cfgelm_type_name[xbt_cfgelm_type_count] = { "int", "double", "string", "boolean", "any", "outofbound" };
 
@@ -78,14 +122,8 @@ const struct xbt_boolean_couple xbt_cfgelm_boolean_values[] = {
   {  NULL,    NULL}
 };
 
-/* Internal stuff used in cache to free a variable */
-static void xbt_cfgelm_free(void *data)
-{
-  delete (xbt_cfgelm_t) data;
-}
-
 /* 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);
+static simgrid::config::ConfigurationElement* xbt_cfgelm_get(xbt_cfg_t cfg, const char *name, e_xbt_cfgelm_type_t type);
 
 /*----[ Memory management ]-----------------------------------------------*/
 /** @brief Constructor
@@ -94,14 +132,13 @@ static xbt_cfgelm_t xbt_cfgelm_get(xbt_cfg_t cfg, const char *name, e_xbt_cfgelm
  */
 xbt_cfg_t xbt_cfg_new(void)
 {
-  return (xbt_cfg_t) xbt_dict_new_homogeneous(&xbt_cfgelm_free);
+  return new simgrid::config::Config();
 }
 
 /** @brief Destructor */
 void xbt_cfg_free(xbt_cfg_t * cfg)
 {
-  XBT_DEBUG("Frees cfg set %p", cfg);
-  xbt_dict_free((xbt_dict_t *) cfg);
+  delete *cfg;
 }
 
 /** @brief Dump a config set for debuging purpose
@@ -112,50 +149,29 @@ void xbt_cfg_free(xbt_cfg_t * cfg)
  */
 void xbt_cfg_dump(const char *name, const char *indent, xbt_cfg_t cfg)
 {
-  xbt_dict_t dict = (xbt_dict_t) cfg;
+  xbt_dict_t dict = cfg->options;
   xbt_dict_cursor_t cursor = NULL;
-  xbt_cfgelm_t variable = NULL;
+  simgrid::config::ConfigurationElement* variable = NULL;
   char *key = NULL;
-  int i;
-  int size;
-  int ival;
-  char *sval;
-  double dval;
 
   if (name)
     printf("%s>> Dumping of the config set '%s':\n", indent, name);
 
   xbt_dict_foreach(dict, cursor, key, variable) {
-    printf("%s  %s:", indent, key);
-
-    size = xbt_dynar_length(variable->content);
-    printf ("%s. Actual size=%d. postset=%p\n",
-            xbt_cfgelm_type_name[variable->type], size, variable->cb_set);
-
+    const char* type_name = xbt_cfgelm_type_name[variable->type];
     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);
-      }
+      printf("%s  %s: ()%s) %i", indent, key, type_name, variable->int_content);
       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);
-      }
+      printf("%s  %s: ()%s) %f", indent, key, type_name, variable->double_content);
       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);
-      }
+      printf("%s  %s: ()%s) %s", indent, key, type_name, variable->string_content);
       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);
-      }
+      printf("%s  %s: ()%s) %s", indent, key, type_name,
+        variable->boolean_content ? "true" : "false");
       break;
     case xbt_cfgelm_alias:
       /* no content */
@@ -182,10 +198,8 @@ void xbt_cfg_dump(const char *name, const char *indent, xbt_cfg_t cfg)
  *  @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)
+static simgrid::config::ConfigurationElement* 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)
 {
   if (*cfg == NULL)
     *cfg = xbt_cfg_new();
@@ -193,70 +207,59 @@ static void xbt_cfg_register(
               "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);
+  simgrid::config::ConfigurationElement* res = (simgrid::config::ConfigurationElement*) xbt_dict_get_or_null((*cfg)->options, name);
   xbt_assert(NULL == res, "Refusing to register the config element '%s' twice.", name);
 
-  res = new s_xbt_cfgelm_t();
+  res = new simgrid::config::ConfigurationElement();
   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->type = type;
-  res->desc = desc;
   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;
+  if (desc)
+    res->desc = desc;
 
+  // Set a default default value:
   switch (type) {
   case xbt_cfgelm_int:
-    res->content = xbt_dynar_new(sizeof(int), NULL);
+    res->int_content = 0;
     break;
   case xbt_cfgelm_double:
-    res->content = xbt_dynar_new(sizeof(double), NULL);
+    res->double_content = 0.0;
     break;
   case xbt_cfgelm_string:
-    res->content = xbt_dynar_new(sizeof(char *), xbt_free_ref);
+    res->string_content = nullptr;
     break;
   case xbt_cfgelm_boolean:
-    res->content = xbt_dynar_new(sizeof(int), NULL);
+    res->boolean_content = false;
     break;
   default:
     XBT_ERROR("%d is an invalid type code", (int)type);
     break;
   }
 
-  xbt_dict_set((xbt_dict_t) * cfg, name, res, NULL);
+  xbt_dict_set((*cfg)->options, name, res, NULL);
+  return res;
 }
 
-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);
+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);
   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);
+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);
   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);
+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);
   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)
+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, type, NULL, cb, data, data_free);
+  xbt_cfg_register(&simgrid_config,name,desc,xbt_cfgelm_boolean,cb_set);
+  xbt_cfg_setdefault_boolean(name, default_value);
 }
 
 void xbt_cfg_register_alias(const char *newname, const char *oldname)
@@ -264,20 +267,20 @@ void xbt_cfg_register_alias(const char *newname, const char *oldname)
   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);
+  simgrid::config::ConfigurationElement* res = (simgrid::config::ConfigurationElement*) xbt_dict_get_or_null(simgrid_config->options, 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);
+  res = (simgrid::config::ConfigurationElement*) xbt_dict_get_or_null(simgrid_config->options, newname);
   xbt_assert(res, "Cannot define an alias to the non-existing option '%s'.", newname);
 
-  res = new s_xbt_cfgelm_t();
+  res = new simgrid::config::ConfigurationElement();
   XBT_DEBUG("Register cfg alias %s -> %s)",oldname,newname);
 
-  res->desc = bprintf("Deprecated alias for %s",newname);
+  res->desc = std::string("Deprecated alias for ")+std::string(newname);
   res->type = xbt_cfgelm_alias;
-  res->content = (xbt_dynar_t)newname;
+  res->string_content = xbt_strdup(newname);
 
-  xbt_dict_set((xbt_dict_t) simgrid_config, oldname, res, NULL);
+  xbt_dict_set(simgrid_config->options, oldname, res, NULL);
 }
 
 /**
@@ -308,7 +311,7 @@ void xbt_cfg_register_str(xbt_cfg_t * cfg, const char *entry)
   xbt_assert(type < xbt_cfgelm_type_count,
       "Invalid type in config element descriptor: %s; Should be one of 'string', 'int' or 'double'.", entry);
 
-  xbt_cfg_register(cfg, entrycpy, NULL, type, NULL, NULL, NULL, NULL);
+  xbt_cfg_register(cfg, entrycpy, NULL, type, NULL);
 
   free(entrycpy);               /* strdup'ed by dict mechanism, but cannot be const */
 }
@@ -318,16 +321,16 @@ void xbt_cfg_aliases(void)
 {
   xbt_dict_cursor_t dict_cursor;
   unsigned int dynar_cursor;
-  xbt_cfgelm_t variable;
+  simgrid::config::ConfigurationElement* 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_dict_foreach(simgrid_config->options, 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);
+    variable = (simgrid::config::ConfigurationElement*) xbt_dict_get(simgrid_config->options, name);
 
     if (variable->type == xbt_cfgelm_alias)
       printf("   %s: %s\n", name, variable->desc.c_str());
@@ -339,65 +342,52 @@ void xbt_cfg_help(void)
 {
   xbt_dict_cursor_t dict_cursor;
   unsigned int dynar_cursor;
-  xbt_cfgelm_t variable;
+  simgrid::config::ConfigurationElement* 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_dict_foreach(simgrid_config->options, 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);
+    variable = (simgrid::config::ConfigurationElement*) xbt_dict_get(simgrid_config->options, name);
     if (variable->type == xbt_cfgelm_alias)
       continue;
 
     printf("   %s: %s\n", name, variable->desc.c_str());
     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);
+        printf("%d\n", variable->int_content);
         break;
       case xbt_cfgelm_double:
-        printf("%f%s", xbt_dynar_get_as(variable->content, i, double), sep);
+        printf("%f\n", variable->double_content);
         break;
       case xbt_cfgelm_string:
-        printf("'%s'%s", xbt_dynar_get_as(variable->content, i, char *), sep);
+        printf("'%s'\n", variable->string_content);
         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);
+      case xbt_cfgelm_boolean:
+        printf("'%s'\n", variable->boolean_content ? "true" : "false");
         break;
-      }
       default:
-        printf("Invalid type!!%s", sep);
+        printf("Invalid type!!\n");
         break;
       }
-    }
+
   }
   xbt_dynar_free(&names);
 }
 
-static xbt_cfgelm_t xbt_cfgelm_get(xbt_cfg_t cfg, const char *name, e_xbt_cfgelm_type_t type)
+static simgrid::config::ConfigurationElement* xbt_cfgelm_get(xbt_cfg_t cfg, const char *name, e_xbt_cfgelm_type_t type)
 {
-  xbt_cfgelm_t res = (xbt_cfgelm_t) xbt_dict_get_or_null((xbt_dict_t) cfg, name);
+  simgrid::config::ConfigurationElement* res = (simgrid::config::ConfigurationElement*) xbt_dict_get_or_null(cfg->options, name);
 
   // 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;
+    const char* newname = res->string_content;
     XBT_INFO("Option %s has been renamed to %s. Consider switching.", name, newname);
     res = xbt_cfgelm_get(cfg, newname, type);
   }
@@ -423,9 +413,9 @@ static xbt_cfgelm_t xbt_cfgelm_get(xbt_cfg_t cfg, const char *name, e_xbt_cfgelm
  */
 e_xbt_cfgelm_type_t xbt_cfg_get_type(xbt_cfg_t cfg, const char *name)
 {
-  xbt_cfgelm_t variable = NULL;
+  simgrid::config::ConfigurationElement* variable = NULL;
 
-  variable = (xbt_cfgelm_t) xbt_dict_get_or_null((xbt_dict_t) cfg, name);
+  variable = (simgrid::config::ConfigurationElement*) xbt_dict_get_or_null(cfg->options, name);
   if (!variable)
     THROWF(not_found_error, 0, "Can't get the type of '%s' since this variable does not exist", name);
 
@@ -579,15 +569,15 @@ void *xbt_cfg_set_as_string(const char *key, const char *value) {
   xbt_ex_t e;
 
   char *ret;
-  volatile xbt_cfgelm_t variable = NULL;
+  volatile simgrid::config::ConfigurationElement* variable = NULL;
   int i;
   double d;
 
   TRY {
     while (variable == NULL) {
-      variable = (xbt_cfgelm_t) xbt_dict_get((xbt_dict_t) simgrid_config, key);
+      variable = (simgrid::config::ConfigurationElement*) xbt_dict_get(simgrid_config->options, key);
       if (variable->type == xbt_cfgelm_alias) {
-        const char *newname = (const char*)variable->content;
+        const char *newname = variable->string_content;
         XBT_INFO("Note: configuration '%s' is deprecated. Please use '%s' instead.", key, newname);
         key = newname;
         variable = NULL;
@@ -637,7 +627,7 @@ void *xbt_cfg_set_as_string(const char *key, const char *value) {
  */
 void xbt_cfg_setdefault_int(const char *name, int val)
 {
-  xbt_cfgelm_t variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_int);
+  simgrid::config::ConfigurationElement* variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_int);
 
   if (variable->isdefault){
     xbt_cfg_set_int(name, val);
@@ -653,7 +643,7 @@ void xbt_cfg_setdefault_int(const char *name, int val)
  */
 void xbt_cfg_setdefault_double(const char *name, double val)
 {
-  xbt_cfgelm_t variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_double);
+  simgrid::config::ConfigurationElement* variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_double);
 
   if (variable->isdefault) {
     xbt_cfg_set_double(name, val);
@@ -669,7 +659,7 @@ void xbt_cfg_setdefault_double(const char *name, double val)
  */
 void xbt_cfg_setdefault_string(const char *name, const char *val)
 {
-  xbt_cfgelm_t variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_string);
+  simgrid::config::ConfigurationElement* variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_string);
 
   if (variable->isdefault){
     xbt_cfg_set_string(name, val);
@@ -685,7 +675,7 @@ void xbt_cfg_setdefault_string(const char *name, const char *val)
  */
 void xbt_cfg_setdefault_boolean(const char *name, const char *val)
 {
-  xbt_cfgelm_t variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_boolean);
+  simgrid::config::ConfigurationElement* variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_boolean);
 
   if (variable->isdefault){
     xbt_cfg_set_boolean(name, val);
@@ -702,14 +692,10 @@ void xbt_cfg_setdefault_boolean(const char *name, const char *val)
  */
 void xbt_cfg_set_int(const char *name, int val)
 {
-  xbt_cfgelm_t variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_int);
-
-  xbt_dynar_set(variable->content, 0, &val);
-
+  simgrid::config::ConfigurationElement* variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_int);
+  variable->int_content = 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 = false;
 }
 
@@ -720,14 +706,10 @@ void xbt_cfg_set_int(const char *name, int val)
  */
 void xbt_cfg_set_double(const char *name, double val)
 {
-  xbt_cfgelm_t variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_double);
-
-  xbt_dynar_set(variable->content, 0, &val);
-
+  simgrid::config::ConfigurationElement* variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_double);
+  variable->double_content = 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 = false;
 }
 
@@ -740,21 +722,27 @@ void xbt_cfg_set_double(const char *name, double val)
  */
 void xbt_cfg_set_string(const char *name, const char *val)
 {
-  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);
-  }
-
-  xbt_dynar_set(variable->content, 0, &newval);
-
+  simgrid::config::ConfigurationElement* variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_string);
+  free(variable->string_content);
+  variable->string_content = xbt_strdup(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 = false;
+
+  if (variable->callback) {
+    try {
+      variable->callback(val);
+    }
+    catch(std::range_error& e) {
+      xbt_die("Invalid flag %s=%s: %s", val, name, e.what());
+    }
+    catch(std::exception& e) {
+      xbt_die("Error for flag %s=%s: %s", val, name, e.what());
+    }
+    catch(...) {
+      xbt_die("Error for flag %s=%s", val, name);
+    }
+  }
 }
 
 /** @brief Set or add a boolean value to \a name within \a cfg
@@ -765,7 +753,7 @@ void xbt_cfg_set_string(const char *name, const char *val)
 void xbt_cfg_set_boolean(const char *name, const char *val)
 {
   int bval=-1;
-  xbt_cfgelm_t variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_boolean);
+  simgrid::config::ConfigurationElement* 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){
@@ -778,12 +766,9 @@ void xbt_cfg_set_boolean(const char *name, const char *val)
     }
   }
   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);
-
+  variable->boolean_content = 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 = false;
 }
 
@@ -791,7 +776,7 @@ void xbt_cfg_set_boolean(const char *name, const char *val)
 /* Say if the value is the default value */
 int xbt_cfg_is_default_value(const char *name)
 {
-  xbt_cfgelm_t variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_any);
+  simgrid::config::ConfigurationElement* variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_any);
   return variable->isdefault;
 }
 
@@ -801,18 +786,11 @@ int xbt_cfg_is_default_value(const char *name)
  * @param name 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)
 {
-  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));
-  }
-
-  return xbt_dynar_get_as(variable->content, 0, int);
+  simgrid::config::ConfigurationElement* variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_int);
+  return variable->int_content;
 }
 
 /** @brief Retrieve a double value of a variable (get a warning if not uniq)
@@ -821,18 +799,11 @@ int xbt_cfg_get_int(const char *name)
  * @param name 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)
 {
-  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));
-  }
-
-  return xbt_dynar_get_as(variable->content, 0, double);
+  simgrid::config::ConfigurationElement* variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_double);
+  return variable->double_content;
 }
 
 /** @brief Retrieve a string value of a variable (get a warning if not uniq)
@@ -841,23 +812,15 @@ double xbt_cfg_get_double(const char *name)
  * @param name 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 NULL 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)
 {
-  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;
-  }
-
-  return xbt_dynar_get_as(variable->content, 0, char *);
+  simgrid::config::ConfigurationElement* variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_string);
+  return variable->string_content;
 }
 
 /** @brief Retrieve a boolean value of a variable (get a warning if not uniq)
@@ -866,50 +829,81 @@ char *xbt_cfg_get_string(const char *name)
  * @param name 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)
 {
-  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));
-  }
-
-  return xbt_dynar_get_as(variable->content, 0, int);
+  simgrid::config::ConfigurationElement* variable = xbt_cfgelm_get(simgrid_config, name, xbt_cfgelm_boolean);
+  return variable->boolean_content;
 }
 
 namespace simgrid {
 namespace config {
 
-static void callCallback(const char* name, void* data)
+bool parseBool(const char* value)
 {
-  (*(std::function<void(const char*)>*) data)(name);
-}
-
-static void freeCallback(void* data)
-{
-  delete (std::function<void(const char*)>*) data;
+  for (int i = 0; xbt_cfgelm_boolean_values[i].true_val != NULL; i++) {
+    if (std::strcmp(value, xbt_cfgelm_boolean_values[i].true_val) == 0)
+      return true;
+    if (std::strcmp(value, xbt_cfgelm_boolean_values[i].false_val) == 0)
+      return false;
+  }
+  throw std::range_error("not a boolean");
+}
+
+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;
+}
+
+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;
 }
 
-void registerConfig(const char* name, const char* description,
-  e_xbt_cfgelm_type_t type,
-  std::function<void(const char*)> callback)
+void declareFlag(const char* name, const char* description,
+  std::function<void(const char* value)> 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);
+  simgrid::config::ConfigurationElement* e = xbt_cfg_register(
+    &simgrid_config, name, description, xbt_cfgelm_string, NULL);
+  e->callback = std::move(callback);
 }
 
 }
 }
 
 #ifdef SIMGRID_TEST
+
+#include <string>
+
 #include "xbt.h"
 #include "xbt/ex.h"
 
+#include <xbt/config.hpp>
+
 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(xbt_cfg);
 
 XBT_TEST_SUITE("config", "Configuration support");
@@ -964,4 +958,27 @@ XBT_TEST_UNIT("use", test_config_use, "Data retrieving tests")
   }
   xbt_cfg_free(&simgrid_config);
 }
+
+XBT_TEST_UNIT("c++flags", test_config_cxx_flags, "C++ flags")
+{
+  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(!bool_flag2, "Check bool2 flag");
+
+  xbt_cfg_free(&simgrid_config);
+}
+
 #endif                          /* SIMGRID_TEST */