interface/config.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        config.h
   3 // Purpose:     interface of wxConfigBase
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows license
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9 /**
  10     @class wxConfigBase
  11     @wxheader{config.h}
  12
  13     wxConfigBase defines the basic interface of all config classes. It can not
  14     be used by itself (it is an abstract base class) and you will always use
  15     one of its derivations: wxFileConfig, wxRegConfig or any other.
  16
  17     However, usually you don't even need to know the precise nature of the
  18     class you're working with but you would just use the wxConfigBase methods.
  19     This allows you to write the same code regardless of whether you're working
  20     with the registry under Win32 or text-based config files under Unix (or
  21     even Windows 3.1 .INI files if you're really unlucky). To make writing the
  22     portable code even easier, wxWidgets provides a typedef wxConfig which is
  23     mapped onto the native wxConfigBase implementation on the given platform:
  24     i.e. wxRegConfig under Win32 and wxFileConfig otherwise.
  25
  26     See @ref overview_config for a description of all features of this class.
  27
  28     It is highly recommended to use static functions Get() and/or Set(), so
  29     please have a look at them.
  30
  31     Related Include Files:
  32
  33     @li @c <wx/config.h>   - Let wxWidgets choose a wxConfig class for your
  34                              platform.
  35     @li @c <wx/confbase.h> - Base config class.
  36     @li @c <wx/fileconf.h> - wxFileConfig class.
  37     @li @c <wx/msw/regconf.h> - wxRegConfig class.
  38
  39
  40     @section configbase_example Example
  41
  42     Here is how you would typically use this class:
  43
  44     @code
  45     // using wxConfig instead of writing wxFileConfig or wxRegConfig enhances
  46     // portability of the code
  47     wxConfig *config = new wxConfig("MyAppName");
  48
  49     wxString str;
  50     if ( config->Read("LastPrompt", &str) ) {
  51         // last prompt was found in the config file/registry and its value is
  52         // now in str
  53         // ...
  54     }
  55     else {
  56         // no last prompt...
  57     }
  58
  59     // another example: using default values and the full path instead of just
  60     // key name: if the key is not found , the value 17 is returned
  61     long value = config->ReadLong("/LastRun/CalculatedValues/MaxValue", 17);
  62
  63     // at the end of the program we would save everything back
  64     config->Write("LastPrompt", str);
  65     config->Write("/LastRun/CalculatedValues/MaxValue", value);
  66
  67     // the changes will be written back automatically
  68     delete config;
  69     @endcode
  70
  71     This basic example, of course, doesn't show all wxConfig features, such as
  72     enumerating, testing for existence and deleting the entries and groups of
  73     entries in the config file, its abilities to automatically store the
  74     default values or expand the environment variables on the fly. However, the
  75     main idea is that using this class is easy and that it should normally do
  76     what you expect it to.
  77
  78     @note In the documentation of this class, the words "config file" also mean
  79           "registry hive" for wxRegConfig and, generally speaking, might mean
  80           any physical storage where a wxConfigBase-derived class stores its
  81           data.
  82
  83
  84     @section configbase_static Static Functions
  85
  86     The static functions provided deal with the "default" config object.
  87     Although its usage is not at all mandatory it may be convenient to use a
  88     global config object instead of creating and deleting the local config
  89     objects each time you need one (especially because creating a wxFileConfig
  90     object might be a time consuming operation). In this case, you may create
  91     this global config object in the very start of the program and Set() it as
  92     the default. Then, from anywhere in your program, you may access it using
  93     the Get() function. This global wxConfig object will be deleted by
  94     wxWidgets automatically if it exists. Note that this implies that if you do
  95     delete this object yourself (usually in wxApp::OnExit()) you must use
  96     Set(@NULL) to prevent wxWidgets from deleting it the second time.
  97
  98     As it happens, you may even further simplify the procedure described above:
  99     you may forget about calling Set(). When Get() is called and there is no
 100     current object, it will create one using Create() function. To disable this
 101     behaviour DontCreateOnDemand() is provided.
 102
 103     @note You should use either Set() or Get() because wxWidgets library itself
 104           would take advantage of it and could save various information in it.
 105           For example wxFontMapper or Unix version of wxFileDialog have the
 106           ability to use wxConfig class.
 107
 108
 109     @section configbase_paths Path Management
 110
 111     As explained in the @ref overview_config "config overview", the config
 112     classes support a file system-like hierarchy of keys (files) and groups
 113     (directories). As in the file system case, to specify a key in the config
 114     class you must use a path to it. Config classes also support the notion of
 115     the current group, which makes it possible to use the relative paths. To
 116     clarify all this, here is an example (it is only for the sake of
 117     demonstration, it doesn't do anything sensible!):
 118
 119     @code
 120     wxConfig *config = new wxConfig("FooBarApp");
 121
 122     // right now the current path is '/'
 123     conf->Write("RootEntry", 1);
 124
 125     // go to some other place: if the group(s) don't exist, they will be created
 126     conf->SetPath("/Group/Subgroup");
 127
 128     // create an entry in subgroup
 129     conf->Write("SubgroupEntry", 3);
 130
 131     // '..' is understood
 132     conf->Write("../GroupEntry", 2);
 133     conf->SetPath("..");
 134
 135     wxASSERT( conf->ReadLong("Subgroup/SubgroupEntry", 0) == 3 );
 136
 137     // use absolute path: it is allowed, too
 138     wxASSERT( conf->ReadLong("/RootEntry", 0) == 1 );
 139     @endcode
 140
 141     It is highly recommended that you restore the path to its old value on
 142     function exit:
 143
 144     @code
 145     void foo(wxConfigBase *config)
 146     {
 147         wxString strOldPath = config->GetPath();
 148
 149         config->SetPath("/Foo/Data");
 150         // ...
 151
 152         config->SetPath(strOldPath);
 153     }
 154     @endcode
 155
 156     Otherwise the assert in the following example will surely fail (we suppose
 157     here that the foo() function is the same as above except that it doesn’t
 158     save and restore the path):
 159
 160     @code
 161     void bar(wxConfigBase *config)
 162     {
 163         config->Write("Test", 17);
 164
 165         foo(config);
 166
 167         // we're reading "/Foo/Data/Test" here! -1 will probably be returned...
 168         wxASSERT( config->ReadLong("Test", -1) == 17 );
 169     }
 170     @endcode
 171
 172     Finally, the path separator in wxConfigBase and derived classes is always
 173     "/", regardless of the platform (i.e. it is not "\\" under Windows).
 174
 175
 176     @section configbase_enumeration Enumeration
 177
 178     The enumeration functions allow you to enumerate all entries and groups in
 179     the config file. All functions here return @false when there are no more
 180     items.
 181
 182     You must pass the same index to GetNext() and GetFirst() (don't modify it).
 183     Please note that it is not the index of the current item (you will have
 184     some great surprises with wxRegConfig if you assume this) and you shouldn't
 185     even look at it: it is just a "cookie" which stores the state of the
 186     enumeration. It can't be stored inside the class because it would prevent
 187     you from running several enumerations simultaneously, that's why you must
 188     pass it explicitly.
 189
 190     Having said all this, enumerating the config entries/groups is very simple:
 191
 192     @code
 193     wxConfigBase *config = ...;
 194     wxArrayString aNames;
 195
 196     // enumeration variables
 197     wxString str;
 198     long dummy;
 199
 200     // first enum all entries
 201     bool bCont = config->GetFirstEntry(str, dummy);
 202     while ( bCont ) {
 203         aNames.Add(str);
 204
 205         bCont = GetConfig()->GetNextEntry(str, dummy);
 206     }
 207
 208     // ... we have all entry names in aNames...
 209
 210     // now all groups...
 211     bCont = GetConfig()->GetFirstGroup(str, dummy);
 212     while ( bCont ) {
 213         aNames.Add(str);
 214
 215         bCont = GetConfig()->GetNextGroup(str, dummy);
 216     }
 217
 218     // ... we have all group (and entry) names in aNames...
 219     @endcode
 220
 221     There are also functions to get the number of entries/subgroups without
 222     actually enumerating them, but you will probably never need them.
 223
 224
 225     @section configbase_keyaccess Key Access
 226
 227     The key access functions are the core of wxConfigBase class: they allow you
 228     to read and write config file data. All Read() functions take a default
 229     value which will be returned if the specified key is not found in the
 230     config file.
 231
 232     Currently, supported types of data are: wxString, @c long, @c double,
 233     @c bool, wxColour and any other types for which the functions
 234     wxToString() and wxFromString() are defined.
 235
 236     Try not to read long values into string variables and vice versa:
 237     although it just might work with wxFileConfig, you will get a system
 238     error with wxRegConfig because in the Windows registry the different
 239     types of entries are indeed used.
 240
 241     Final remark: the @a szKey parameter for all these functions can
 242     contain an arbitrary path (either relative or absolute), not just the
 243     key name.
 244
 245     @beginWxPythonOnly
 246     In place of a single overloaded method name, wxPython implements the
 247     following methods:
 248     - Read(key, default="") - Returns a string.
 249     - ReadInt(key, default=0) - Returns an integer.
 250     - ReadFloat(key, default=0.0) - Returns a floating point number.
 251     - ReadBool(key, default=0) - Returns a boolean.
 252     - Write(key, value) - Writes a string.
 253     - WriteInt(key, value) - Writes an int.
 254     - WriteFloat(key, value) - Writes a floating point number.
 255     @endWxPythonOnly
 256
 257
 258     @library{wxbase}
 259     @category{misc}
 260 */
 261 class wxConfigBase : public wxObject
 262 {
 263 public:
 264     /**
 265         This is the default and only constructor of the wxConfigBase class, and
 266         derived classes.
 267
 268         @param appName
 269             The application name. If this is empty, the class will normally use
 270             wxApp::GetAppName() to set it. The application name is used in the
 271             registry key on Windows, and can be used to deduce the local
 272             filename parameter if that is missing.
 273         @param vendorName
 274             The vendor name. If this is empty, it is assumed that no vendor
 275             name is wanted, if this is optional for the current config class.
 276             The vendor name is appended to the application name for
 277             wxRegConfig.
 278         @param localFilename
 279             Some config classes require a local filename. If this is not
 280             present, but required, the application name will be used instead.
 281         @param globalFilename
 282             Some config classes require a global filename. If this is not
 283             present, but required, the application name will be used instead.
 284         @param style
 285             Can be one of wxCONFIG_USE_LOCAL_FILE and wxCONFIG_USE_GLOBAL_FILE.
 286             The style interpretation depends on the config class and is ignored
 287             by some implementations. For wxFileConfig, these styles determine
 288             whether a local or global config file is created or used: if
 289             wxCONFIG_USE_GLOBAL_FILE is used, then settings are read from the
 290             global config file and if wxCONFIG_USE_LOCAL_FILE is used, settings
 291             are read from and written to local config file (if they are both
 292             set, global file is read first, then local file, overwriting global
 293             settings). If the flag is present but the parameter is empty, the
 294             parameter will be set to a default. If the parameter is present but
 295             the style flag not, the relevant flag will be added to the style.
 296             For wxRegConfig, thie GLOBAL flag refers to HKLM key while LOCAL
 297             one is for the usual HKCU one.
 298             @n For wxFileConfig you can also add wxCONFIG_USE_RELATIVE_PATH by
 299             logically or'ing it to either of the _FILE options to tell
 300             wxFileConfig to use relative instead of absolute paths.
 301             @n On non-VMS Unix systems, the default local configuration file is
 302             "~/.appname". However, this path may be also used as user data
 303             directory (see wxStandardPaths::GetUserDataDir()) if the
 304             application has several data files. In this case
 305             wxCONFIG_USE_SUBDIR flag, which changes the default local
 306             configuration file to "~/.appname/appname" should be used. Notice
 307             that this flag is ignored if localFilename is provided.
 308             wxCONFIG_USE_SUBDIR is new since wxWidgets version 2.8.2.
 309             @n For wxFileConfig, you can also add
 310             wxCONFIG_USE_NO_ESCAPE_CHARACTERS which will turn off character
 311             escaping for the values of entries stored in the config file: for
 312             example a foo key with some backslash characters will be stored as
 313             "foo=C:\mydir" instead of the usual storage of "foo=C:\\mydir".
 314             @n The wxCONFIG_USE_NO_ESCAPE_CHARACTERS style can be helpful if your
 315             config file must be read or written to by a non-wxWidgets program
 316             (which might not understand the escape characters). Note, however,
 317             that if wxCONFIG_USE_NO_ESCAPE_CHARACTERS style is used, it is is
 318             now your application's responsibility to ensure that there is no
 319             newline or other illegal characters in a value, before writing that
 320             value to the file.
 321         @param conv
 322             This parameter is only used by wxFileConfig when compiled in
 323             Unicode mode. It specifies the encoding in which the configuration
 324             file is written.
 325
 326         @remarks By default, environment variable expansion is on and recording
 327                  defaults is off.
 328     */
 329     wxConfigBase(const wxString& appName = wxEmptyString,
 330                  const wxString& vendorName = wxEmptyString,
 331                  const wxString& localFilename = wxEmptyString,
 332                  const wxString& globalFilename = wxEmptyString,
 333                  long style = 0,
 334                  const wxMBConv& conv = wxConvAuto());
 335
 336     /**
 337         Empty but ensures that dtor of all derived classes is virtual.
 338     */
 339     ~wxConfigBase();
 340
 341
 342     /**
 343         @name Path Management
 344
 345         See @ref configbase_paths
 346     */
 347     //@{
 348
 349     /**
 350         Retrieve the current path (always as absolute path).
 351     */
 352     const wxString GetPath() const;
 353
 354     /**
 355         Set current path: if the first character is '/', it is the absolute
 356         path, otherwise it is a relative path. '..' is supported. If @a strPath
 357         doesn't exist it is created.
 358     */
 359     void SetPath(const wxString& strPath);
 360
 361     //@}
 362
 363
 364     /**
 365         @name Enumeration
 366
 367         See @ref configbase_enumeration
 368     */
 369     //@{
 370
 371     /**
 372         Gets the first entry.
 373
 374         @beginWxPythonOnly
 375         The wxPython version of this method returns a 3-tuple consisting of the
 376         continue flag, the value string, and the index for the next call.
 377         @endWxPythonOnly
 378     */
 379     bool GetFirstEntry(wxString& str, long& index) const;
 380
 381     /**
 382         Gets the first group.
 383
 384         @beginWxPythonOnly
 385         The wxPython version of this method returns a 3-tuple consisting of the
 386         continue flag, the value string, and the index for the next call.
 387         @endWxPythonOnly
 388     */
 389     bool GetFirstGroup(wxString& str, long& index) const;
 390
 391     /**
 392         Gets the next entry.
 393
 394         @beginWxPythonOnly
 395         The wxPython version of this method returns a 3-tuple consisting of the
 396         continue flag, the value string, and the index for the next call.
 397         @endWxPythonOnly
 398     */
 399     bool GetNextEntry(wxString& str, long& index) const;
 400
 401     /**
 402         Gets the next group.
 403
 404         @beginWxPythonOnly
 405         The wxPython version of this method returns a 3-tuple consisting of the
 406         continue flag, the value string, and the index for the next call.
 407         @endWxPythonOnly
 408     */
 409     bool GetNextGroup(wxString& str, long& index) const;
 410
 411     /**
 412         Get number of entries in the current group.
 413     */
 414     uint GetNumberOfEntries(bool bRecursive = false) const;
 415
 416     /**
 417         Get number of entries/subgroups in the current group, with or without
 418         its subgroups.
 419     */
 420     uint GetNumberOfGroups(bool bRecursive = false) const;
 421
 422     //@}
 423
 424
 425     enum EntryType
 426     {
 427         Type_Unknown,
 428         Type_String,
 429         Type_Boolean,
 430         Type_Integer,
 431         Type_Float
 432     };
 433
 434     /**
 435         @name Tests of Existence
 436     */
 437     //@{
 438
 439     /**
 440         @return @true if either a group or an entry with a given name exists.
 441     */
 442     bool Exists(wxString& strName) const;
 443
 444     /**
 445         Returns the type of the given entry or @e Unknown if the entry doesn't
 446         exist. This function should be used to decide which version of Read()
 447         should be used because some of wxConfig implementations will complain
 448         about type mismatch otherwise: e.g., an attempt to read a string value
 449         from an integer key with wxRegConfig will fail.
 450     */
 451     wxConfigBase::EntryType GetEntryType(const wxString& name) const;
 452
 453     /**
 454         @return @true if the entry by this name exists.
 455     */
 456     bool HasEntry(wxString& strName) const;
 457
 458     /**
 459         @return @true if the group by this name exists.
 460     */
 461     bool HasGroup(const wxString& strName) const;
 462
 463     //@}
 464
 465
 466     /**
 467         @name Miscellaneous Functions
 468     */
 469     //@{
 470
 471     /**
 472         Returns the application name.
 473     */
 474     wxString GetAppName() const;
 475
 476     /**
 477         Returns the vendor name.
 478     */
 479     wxString GetVendorName() const;
 480
 481     //@}
 482
 483
 484     /**
 485         @name Key Access
 486
 487         See @ref configbase_keyaccess
 488     */
 489     //@{
 490
 491     /**
 492         Permanently writes all changes (otherwise, they're only written from
 493         object's destructor).
 494     */
 495     bool Flush(bool bCurrentOnly = false);
 496
 497     /**
 498         Read a string from the key, returning @true if the value was read. If
 499         the key was not found, @a str is not changed.
 500     */
 501     bool Read(const wxString& key, wxString* str) const;
 502     /**
 503         Read a string from the key. The default value is returned if the key
 504         was not found.
 505
 506         @return @true if value was really read, @false if the default was used.
 507     */
 508     const bool Read(const wxString& key, wxString* str,
 509                       const wxString& defaultVal) const;
 510     /**
 511         Another version of Read(), returning the string value directly.
 512     */
 513     const wxString Read(const wxString& key,
 514                          const wxString& defaultVal) const;
 515     /**
 516         Reads a long value, returning @true if the value was found. If the
 517         value was not found, @a l is not changed.
 518     */
 519     const bool Read(const wxString& key, long* l) const;
 520     /**
 521         Reads a long value, returning @true if the value was found. If the
 522         value was not found, @a defaultVal is used instead.
 523     */
 524     const bool Read(const wxString& key, long* l,
 525                     long defaultVal) const;
 526     /**
 527         Reads a double value, returning @true if the value was found. If the
 528         value was not found, @a d is not changed.
 529     */
 530     const bool Read(const wxString& key, double* d) const;
 531     /**
 532         Reads a double value, returning @true if the value was found. If the
 533         value was not found, @a defaultVal is used instead.
 534     */
 535     const bool Read(const wxString& key, double* d,
 536                      double defaultVal) const;
 537     /**
 538         Reads a bool value, returning @true if the value was found. If the
 539         value was not found, @a b is not changed.
 540     */
 541     const bool Read(const wxString& key, bool* b) const;
 542     /**
 543         Reads a bool value, returning @true if the value was found. If the
 544         value was not found, @a defaultVal is used instead.
 545     */
 546     const bool Read(const wxString& key, bool* d,
 547                      bool defaultVal) const;
 548     /**
 549         Reads a binary block, returning @true if the value was found. If the
 550         value was not found, @a buf is not changed.
 551     */
 552     const bool Read(const wxString& key, wxMemoryBuffer* buf) const;
 553     /**
 554         Reads a value of type T, for which function wxFromString() is defined,
 555         returning @true if the value was found. If the value was not found,
 556         @a value is not changed.
 557     */
 558     const bool Read(const wxString& key, T* value) const;
 559     /**
 560         Reads a value of type T, for which function wxFromString() is defined,
 561         returning @true if the value was found. If the value was not found,
 562         @a defaultVal is used instead.
 563     */
 564     const bool Read(const wxString& key, T* value,
 565                      const T& defaultVal) const;
 566
 567     /**
 568         Reads a bool value from the key and returns it. @a defaultVal is
 569         returned if the key is not found.
 570     */
 571     long ReadBool(const wxString& key, bool defaultVal) const;
 572
 573     /**
 574         Reads a double value from the key and returns it. @a defaultVal is
 575         returned if the key is not found.
 576     */
 577     long ReadDouble(const wxString& key, double defaultVal) const;
 578
 579     /**
 580         Reads a long value from the key and returns it. @a defaultVal is
 581         returned if the key is not found.
 582     */
 583     long ReadLong(const wxString& key, long defaultVal) const;
 584
 585     /**
 586         Reads a value of type T (for which the function wxFromString() must be
 587         defined) from the key and returns it. @a defaultVal is returned if the
 588         key is not found.
 589     */
 590     T ReadObject(const wxString& key, T const& defaultVal) const;
 591
 592     /**
 593         Writes the wxString value to the config file and returns @true on
 594         success.
 595     */
 596     bool Write(const wxString& key, const wxString& value);
 597     /**
 598         Writes the long value to the config file and returns @true on success.
 599     */
 600     bool Write(const wxString& key, long value);
 601     /**
 602         Writes the double value to the config file and returns @true on
 603         success.
 604     */
 605     bool Write(const wxString& key, double value);
 606     /**
 607         Writes the bool value to the config file and returns @true on success.
 608     */
 609     bool Write(const wxString& key, bool value);
 610     /**
 611         Writes the wxMemoryBuffer value to the config file and returns @true on
 612         success.
 613     */
 614     bool Write(const wxString& key, const wxMemoryBuffer& buf);
 615     /**
 616         Writes the specified value to the config file and returns @true on
 617         success. The function wxToString() must be defined for type @e T.
 618     */
 619     bool Write(const wxString& key, T const& buf);
 620
 621     //@}
 622
 623
 624     /**
 625         @name Rename Entries/Groups
 626
 627         These functions allow renaming entries or subgroups of the current
 628         group. They will return @false on error, typically because either the
 629         entry/group with the original name doesn't exist, because the
 630         entry/group with the new name already exists or because the function is
 631         not supported in this wxConfig implementation.
 632     */
 633     //@{
 634
 635     /**
 636         Renames an entry in the current group. The entries names (both the old
 637         and the new one) shouldn't contain backslashes, i.e. only simple names
 638         and not arbitrary paths are accepted by this function.
 639
 640         @return @false if @a oldName doesn't exist or if @a newName already
 641                 exists.
 642     */
 643     bool RenameEntry(const wxString& oldName, const wxString& newName);
 644
 645     /**
 646         Renames a subgroup of the current group. The subgroup names (both the
 647         old and the new one) shouldn't contain backslashes, i.e. only simple
 648         names and not arbitrary paths are accepted by this function.
 649
 650         @return @false if @a oldName doesn't exist or if @a newName already
 651                 exists.
 652     */
 653     bool RenameGroup(const wxString& oldName, const wxString& newName);
 654
 655     //@}
 656
 657
 658     /**
 659         @name Delete Entries/Groups
 660
 661         These functions delete entries and/or groups of entries from the config
 662         file. DeleteAll() is especially useful if you want to erase all traces
 663         of your program presence: for example, when you uninstall it.
 664     */
 665     //@{
 666
 667     /**
 668         Delete the whole underlying object (disk file, registry key, ...).
 669         Primarly for use by uninstallation routine.
 670     */
 671     bool DeleteAll();
 672
 673     /**
 674         Deletes the specified entry and the group it belongs to if it was the
 675         last key in it and the second parameter is @true.
 676     */
 677     bool DeleteEntry(const wxString& key,
 678                      bool bDeleteGroupIfEmpty = true);
 679
 680     /**
 681         Delete the group (with all subgroups). If the current path is under the
 682         group being deleted it is changed to its deepest still existing
 683         component. E.g. if the current path is @c "/A/B/C/D" and the group @c C
 684         is deleted, the path becomes @c "/A/B".
 685     */
 686     bool DeleteGroup(const wxString& key);
 687
 688     //@}
 689
 690
 691     /**
 692         @name Options
 693
 694         Some aspects of wxConfigBase behaviour can be changed during run-time.
 695         The first of them is the expansion of environment variables in the
 696         string values read from the config file: for example, if you have the
 697         following in your config file:
 698
 699         @code
 700         # config file for my program
 701         UserData = $HOME/data
 702
 703         # the following syntax is valud only under Windows
 704         UserData = %windir%\\data.dat
 705         @endcode
 706
 707         The call to Read("UserData") will return something like
 708         @c "/home/zeitlin/data" on linux for example.
 709
 710         Although this feature is very useful, it may be annoying if you read a
 711         value which containts '$' or '%' symbols (% is used for environment
 712         variables expansion under Windows) which are not used for environment
 713         variable expansion. In this situation you may call
 714         SetExpandEnvVars(@false) just before reading this value and
 715         SetExpandEnvVars(@true) just after. Another solution would be to prefix
 716         the offending symbols with a backslash.
 717     */
 718     //@{
 719
 720     /**
 721         Returns @true if we are expanding environment variables in key values.
 722     */
 723     bool IsExpandingEnvVars() const;
 724
 725     /**
 726         Returns @true if we are writing defaults back to the config file.
 727     */
 728     bool IsRecordingDefaults() const;
 729
 730     /**
 731         Determine whether we wish to expand environment variables in key
 732         values.
 733     */
 734     void SetExpandEnvVars(bool bDoIt = true);
 735
 736     /**
 737         Sets whether defaults are recorded to the config file whenever an
 738         attempt to read the value which is not present in it is done.
 739
 740         If on (default is off) all default values for the settings used by the
 741         program are written back to the config file. This allows the user to
 742         see what config options may be changed and is probably useful only for
 743         wxFileConfig.
 744     */
 745     void SetRecordDefaults(bool bDoIt = true);
 746
 747     //@}
 748
 749
 750     /**
 751         Create a new config object: this function will create the "best"
 752         implementation of wxConfig available for the current platform, see
 753         comments near the definition of wxCONFIG_WIN32_NATIVE for details. It
 754         returns the created object and also sets it as the current one.
 755     */
 756     static wxConfigBase* Create();
 757
 758     /**
 759         Calling this function will prevent @e Get() from automatically creating
 760         a new config object if the current one is @NULL. It might be useful to
 761         call it near the program end to prevent "accidental" creation of a new
 762         config object.
 763     */
 764     static void DontCreateOnDemand();
 765
 766     /**
 767         Get the current config object. If there is no current object and
 768         @a CreateOnDemand is @true, this creates one (using Create()) unless
 769         DontCreateOnDemand() was called previously.
 770     */
 771     static wxConfigBase* Get(bool CreateOnDemand = true);
 772
 773     /**
 774         Sets the config object as the current one, returns the pointer to the
 775         previous current object (both the parameter and returned value may be
 776         @NULL).
 777     */
 778     static wxConfigBase* Set(wxConfigBase* pConfig);
 779 };
 780