Why std::string is used for the file paths?
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Why std::string is used for the file paths?
by Roman R
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Why std::string is used for the file paths?
Most of Miscellaneous Utility Functions (http://www.gtkmm.org/docs/glibmm-2.4/docs/reference/html/group__MiscUtils.html), Gio::File, Gtk::Image::set, Gdk::Pixbuf::create_from_file and so on. Why not just use Glib:ustring everywhere? For example, this simple code will cause a crash: Gtk::Image image; Glib::ustring path("image.png"); image.set(path); Why I should write image.set(path.raw()); to prevent this crash? Thanks. _______________________________________________ gtkmm-list mailing list gtkmm-list@... http://mail.gnome.org/mailman/listinfo/gtkmm-list |
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Re: Why std::string is used for the file paths?
by milosz derezynski
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Filesystems aren't in any particular encoding; there is no such thing as a "string class for file paths". On UNIX a file path is just a sequence of 8-bit characters, for which std::string is suited best, and for which Glib::ustring isn't needed. If any of the mentioned functions would take an Glib::ustring, the ustring would need to be passed to the relevant internal function using ::raw() anyway which would make any UTF-8ness it might or might not have there unneccessary.
2008/7/13 Roman Yazmin <roman.yazmin@...>: Why std::string is used for the file paths? -- ------------ Please note that according to the German law on data retention, information on every electronic information exchange with me is retained for a period of six months. [Bitte beachten Sie, dass dem Gesetz zur Vorratsdatenspeicherung zufolge jeder elektronische Kontakt mit mir sechs Monate lang gespeichert wird.] _______________________________________________ gtkmm-list mailing list gtkmm-list@... http://mail.gnome.org/mailman/listinfo/gtkmm-list |
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Re: Why std::string is used for the file paths?
by Roman R
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If library has own "string" class, and it is used, it should be used everywhere.
No matter what happens internally. Library interface should be common. Why we need this "string hell"? On Sun, Jul 13, 2008 at 6:03 AM, Milosz Derezynski <internalerror@...> wrote: Filesystems aren't in any particular encoding; there is no such thing as a "string class for file paths". On UNIX a file path is just a sequence of 8-bit characters, for which std::string is suited best, and for which Glib::ustring isn't needed. If any of the mentioned functions would take an Glib::ustring, the ustring would need to be passed to the relevant internal function using ::raw() anyway which would make any UTF-8ness it might or might not have there unneccessary. _______________________________________________ gtkmm-list mailing list gtkmm-list@... http://mail.gnome.org/mailman/listinfo/gtkmm-list |
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Re: Why std::string is used for the file paths?
by Toralf Lund
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Roman Yazmin wrote:
> If library has own "string" class, and it is used, it should be used > everywhere. Gtkmm doesn't have its own "string" class. It has a special class for UTF-8 encoded strings. That's what Glib::ustring is. > No matter what happens internally. Library interface should be common. > Why we need this "string hell"? > > > On Sun, Jul 13, 2008 at 6:03 AM, Milosz Derezynski > <internalerror@... <mailto:internalerror@...>> wrote: > > Filesystems aren't in any particular encoding; there is no such > thing as a "string class for file paths". On UNIX a file path is > just a sequence of 8-bit characters, for which std::string is > suited best, and for which Glib::ustring isn't needed. If any of > the mentioned functions would take an Glib::ustring, the ustring > would need to be passed to the relevant internal function using > ::raw() anyway which would make any UTF-8ness it might or might > not have there unneccessary. > > 2008/7/13 Roman Yazmin <roman.yazmin@... > <mailto:roman.yazmin@...>>: > > Why std::string is used for the file paths? > > Most of Miscellaneous Utility Functions > (http://www.gtkmm.org/docs/glibmm-2.4/docs/reference/html/group__MiscUtils.html), > Gio::File, Gtk::Image::set, Gdk::Pixbuf::create_from_file and > so on. > Why not just use Glib:ustring everywhere? > > For example, this simple code will cause a crash: > Gtk::Image image; > Glib::ustring path("image.png"); > image.set(path); > > Why I should write image.set(path.raw()); to prevent this crash? > > Thanks. > > _______________________________________________ > gtkmm-list mailing list > gtkmm-list@... <mailto:gtkmm-list@...> > http://mail.gnome.org/mailman/listinfo/gtkmm-list > > > > > -- > ------------ > Please note that according to the German law on data retention, > information on every electronic information exchange with me is > retained for a period of six months. > [Bitte beachten Sie, dass dem Gesetz zur Vorratsdatenspeicherung > zufolge > jeder elektronische Kontakt mit mir sechs Monate lang gespeichert > wird.] > > > ------------------------------------------------------------------------ > > _______________________________________________ > gtkmm-list mailing list > gtkmm-list@... > http://mail.gnome.org/mailman/listinfo/gtkmm-list > -- Toralf Lund <toralf@...> +47 66 85 51 22 ProCaptura AS +47 66 85 51 00 (switchboard) http://www.procaptura.com/ +47 66 85 51 01 (fax) _______________________________________________ gtkmm-list mailing list gtkmm-list@... http://mail.gnome.org/mailman/listinfo/gtkmm-list |
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Re: Why std::string is used for the file paths?
by Roman R
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Gtkmm doesn't have its own "string" class. It has a special class for UTF-8 encoded strings. That's what Glib::ustring is. And all library use this special class for UTF-8 encoded strings. And must be used for file paths also. If not, please show me the benefits of using std::string for file paths instead of ustring. _______________________________________________ gtkmm-list mailing list gtkmm-list@... http://mail.gnome.org/mailman/listinfo/gtkmm-list |
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Re: Why std::string is used for the file paths?
by Toralf Lund
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Roman Yazmin wrote:
> > Gtkmm doesn't have its own "string" class. It has a special class > for UTF-8 encoded strings. That's what Glib::ustring is. > > > And all library use this special class for UTF-8 encoded strings. And > must be used for file paths also. > If not, please show me the benefits of using std::string for file > paths instead of ustring. I think you are looking at this from the wrong side, so as to speak. As far as I understand, Glib::ustring is not intended as a "separate" string class. It may be implemented somewhat separately for some obscure technical reason, but you should view it as a specialisation of std::string with additional support for UTF-8 encoding and variable length characters. So, generally std::string is used all over the place. In some places, a specialised class with support for a special case of a string, i.e. an UTF-8 encoded text, is needed. This is where Glib::ustring is used. But Glib::ustring "is a" std::string, at least conceptually. Other places, strings are just general character sequences, so the generic string class is used directly. std::string, that is. Also using the current Glib::ustring implementation for the more general strings may work from a technical perspective, but it would break with the normal rules for object orientation, and Glib::ustring *might* also be implemented in such a way that non-UTF-8 strings would simply be rejected. - Toralf _______________________________________________ gtkmm-list mailing list gtkmm-list@... http://mail.gnome.org/mailman/listinfo/gtkmm-list |
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Re: Why std::string is used for the file paths?
by Murray Cumming
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On Mon, 2008-07-14 at 12:52 +0400, Roman Yazmin wrote:
> Gtkmm doesn't have its own "string" class. It has a special > class for UTF-8 encoded strings. That's what Glib::ustring is. > > And all library use this special class for UTF-8 encoded strings. And > must be used for file paths also. > If not, please show me the benefits of using std::string for file > paths instead of ustring. It makes it clear that you need to think about what encoding is used for the filename, and does not offer you an API to manipulate non-UTF8 characters as UTF-8. For instance, it makes it clear that you should probably use filename_to_utf8() and filename_from_utf8() when showing the filepath to a user or interpreting a filepath entered by a user. http://www.gtkmm.org/docs/glibmm-2.4/docs/reference/html/group__CharsetConv.html#g2bd94064ad97b43324a7854b62f0835b You really still need to be aware of these encodings on modern computer system, unfortunately. It also avoids an unwanted conversion when writing a filepath out to a C ++ standard stream, such as std::cout. -- murrayc@... www.murrayc.com www.openismus.com _______________________________________________ gtkmm-list mailing list gtkmm-list@... http://mail.gnome.org/mailman/listinfo/gtkmm-list |
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Re: Why std::string is used for the file paths?
by Roman R
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Much clear to use UTF8 (ustring) everywhere.
filename_to_utf8, filename_from_utf8(), etc should be hidden and should be used internally by library if neccessary. Most modern operating systems use unicode for filenames/paths (UTF8 encoded or wide chars, doesn't matter). By using ustring we simply remove the possibility of writing code that don't care about this. The code written once will work on any system. On Mon, Jul 14, 2008 at 1:33 PM, Murray Cumming <murrayc@...> wrote:
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