Re: Problem swapping GtkScrolledWindow contents on the fly
Still getting strange results with this. Ive posted a skeleton app at www.simple.org/TCSAdminGTK.tar which is a single source file which can be comiled with g++ ./main.cpp `pkg-config --cflags --libs libgnome-2.0 libgnomeui-2.0 libglade-2.0` When you click one of the options on the left the contents changes on the right. At present only 'General' and 'Calls' are implemented. As you can see the first time you click one of these the widgets show correctly but the second time you click it they don't but you get no error on the console either. The guts of the issue are contained in the functions showGeneralPage() and showCallsPage() The closest explaination Ive been able to find is that the call to gtk_container_remove (GTK_CONTAINER (rightpanescrollview),gtk_bin_get_child(GTK_BIN(rightpanescrollview))); is deleting the widgets as well as just removing them from the container, but theres no error to suggest this, and I would have thought the calls to gtk_widget_ref(callspage) or gtk_widget_ref(generalpage) would have prevented this. There must be something very simple Im overlooking here. Any ideas? Thanks Andrew ___ gtk-app-devel-list mailing list gtk-app-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
gtk_builder_add_from_file error handling
I just found that with a builder file with a syntax error my app crashed
with:
*** glibc detected *** ./packager: double free or corruption (out):
0x09aa33d0 ***
I think I'm using gtkbuilder error handling in the right way and
documentation does not suggest my how to use it:
GError *err = NULL;
if (!gtk_builder_add_from_file(builder_, myfile.xml, erro)) {
}
--
Ing. Gabriele Greco, DARTS Engineering
Tel: +39-0105761240 Fax: +39-0105760224
s-mail: Via G.T. Invrea 14 - 16129 GENOVA (ITALY)
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gtk_builder_add_from_file error handling
Sorry last message was sent by accident pushing an hotkey while editing...
This should be the complete version of my question:
I just found that with a builder file with a syntax error my app crashed
with:
*** glibc detected *** ./packager: double free or corruption (out):
0x09aa33d0 ***
I think I'm using gtkbuilder error handling in the right way and
documentation does not suggest my how to use it:
GError *err = NULL;
if (!gtk_builder_add_from_file(builder_, myfile.xml, err)) {
if (err) {
cerr builder load fail: err-message '\n';
g_free(err); // commenting this solves the crash but other gtk apis
// and examples I've found always free error handling
pointers
}
else
cerr builder load fail, unknown error\n;
return false;
}
--
Bye,
Gabry
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Re: gtk_builder_add_from_file error handling
On Wed, 2010-01-13 at 11:52 +0100, Gabriele Greco wrote:
GError *err = NULL;
if (!gtk_builder_add_from_file(builder_, myfile.xml, err)) {
if (err) {
cerr builder load fail: err-message '\n';
g_free(err); // commenting this solves the crash but other gtk apis
// and examples I've found always free error handling
pointers
I don't know gtkmm, but at least in C GErrors are freed with
g_error_free(err).
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Re: Problem swapping GtkScrolledWindow contents on the fly
On Wed, Jan 13, 2010 at 10:33:07AM +, Andrew Wood wrote: Still getting strange results with this. Ive posted a skeleton app at www.simple.org/TCSAdminGTK.tar which is a single source file which can be comiled with g++ ./main.cpp `pkg-config --cflags --libs libgnome-2.0 libgnomeui-2.0 libglade-2.0` When you click one of the options on the left the contents changes on the right. At present only 'General' and 'Calls' are implemented. As you can see the first time you click one of these the widgets show correctly but the second time you click it they don't but you get no error on the console either. The guts of the issue are contained in the functions showGeneralPage() and showCallsPage() The closest explaination Ive been able to find is that the call to gtk_container_remove (GTK_CONTAINER (rightpanescrollview),gtk_bin_get_child(GTK_BIN(rightpanescrollview))); is deleting the widgets as well as just removing them from the container, but theres no error to suggest this, and I would have thought the calls to gtk_widget_ref(callspage) or gtk_widget_ref(generalpage) would have prevented this. There must be something very simple Im overlooking here. Any ideas? Indeed, the children get removed from the container when the page is removed so the next time it's show it's empty. This is somehow caused by the widget being constructed by libglade because if you construct it manually, it does no happen. I can't help with libglade and it's already obsolete... BTW please don't use things like gtk_widget_ref() that were deprectated many years ago. Yeti ___ gtk-app-devel-list mailing list gtk-app-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
Re: gtk_builder_add_from_file error handling
GError *err = NULL;
if (!gtk_builder_add_from_file(builder_, myfile.xml, err)) {
if (err) {
g_free(err); // commenting this solves the crash but other gtk apis
I don't know gtkmm, but at least in C GErrors are freed with
g_error_free(err).
You are obviously right. I always used g_free() to free errors, my fault.
I've grepped tons of sources and I had everywhere the code bugged, then I
googled around to search some more examples and I've found there are a lot
of other sources in the net where a GError is freed with g_free, I think
improving the documentation of the functions that use a GError as input
parameter may help programmers do not write wrong code in this situation.
--
Bye,
Gabry
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Re: gtk_builder_add_from_file error handling
On Wed, Jan 13, 2010 at 04:48:29PM +0100, Gabriele Greco wrote: ... I've found there are a lot of other sources in the net where a GError is freed with g_free, I think improving the documentation of the functions that use a GError as input parameter may help programmers do not write wrong code in this situation. The proper handling of GErrors is described in great detail in the GError documentation. I don't think it is reasonable to explain this in the documentation of every function that uses GError to report errors as there are almost 80 of them just in Gtk+ (and over 400 in GLib, and many more elsewhere). Yeti ___ gtk-app-devel-list mailing list gtk-app-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
Re: gtk_builder_add_from_file error handling
The proper handling of GErrors is described in great detail in the GError documentation. I don't think it is reasonable to explain this in the documentation of every function that uses GError to report errors as there are almost 80 of them just in Gtk+ (and over 400 in GLib, and many more elsewhere). I think, and I'm used to see in almost every framework documentations, that every time a function allocates something that the API user must free himself the documentation should explicitly say so. Documentation should be redundant when it may cause errors the fact it is not. This is the case of GError and for instance gtk_ui_manager_add_ui_from_file/string and gtk_builder_add_from_file/string. It's not a case that in UI toolkit debates one of the most common criticism to GTK is the lack of documentation. -- Bye, Gabry ___ gtk-app-devel-list mailing list gtk-app-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
Re: gtk_builder_add_from_file error handling
On Wed, 2010-01-13 at 17:18 +0100, Gabriele Greco wrote: The proper handling of GErrors is described in great detail in the GError documentation. I don't think it is reasonable to explain this in the documentation of every function that uses GError to report errors as there are almost 80 of them just in Gtk+ (and over 400 in GLib, and many more elsewhere). I think, and I'm used to see in almost every framework documentations, that every time a function allocates something that the API user must free himself the documentation should explicitly say so. Documentation should be redundant when it may cause errors the fact it is not. that's why gtk-doc creates cross-links for each data type. This is the case of GError and for instance gtk_ui_manager_add_ui_from_file/string and gtk_builder_add_from_file/string. It's not a case that in UI toolkit debates one of the most common criticism to GTK is the lack of documentation. the lack of documentation refers to empty (or FIXME) sections of the API reference and to high-level documentation. the fact that a non-NULL GError must be freed using the corresponding GError free function is documented in great detail and that documentation linked by every function in a gtk-doc-generated API reference and part of the behavior of the framework. the API reference does not gain anything by adding: @error: a return location for a #GError or %NULL. + Use g_error_free() to free the #GError if @error is not %NULL + after calling this function for each and every GError-using function. you'd just be writing redundant documentation. if you can't be bothered to follow through a link then you're probably using g_free() on every single data structure, which yields interesting results when done on, say, GString or worse GObject. ciao, Emmanuele. -- W: http://www.emmanuelebassi.name B: http://blogs.gnome.org/ebassi ___ gtk-app-devel-list mailing list gtk-app-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
Re: gtk_builder_add_from_file error handling
On Wed, Jan 13, 2010 at 05:18:04PM +0100, Gabriele Greco wrote: I think, and I'm used to see in almost every framework documentations, that every time a function allocates something that the API user must free himself the documentation should explicitly say so. Documentation should be redundant when it may cause errors the fact it is not. This is the case of GError and for instance gtk_ui_manager_add_ui_from_file/string and gtk_builder_add_from_file/string. I'm sorry but this is nonsense. 1) The problem was not whether you had to free the error or not. You just used the wrong function to free it. Very few data structures used in GLib can be freed by mere g_free(), the only common exception is the raw C string -- but that's not a GLib data type. GErrors are no exception in that. 2) GError is the try/catch mechanism (well, a rough approximation of that it permitted by C semantics). You must read the GError documentation to use it properly. If you don't know how try/catch works in any language, the only thing you can do is to ignore the possibility of failure. That's exactly what passing NULL for the error acomplishes with GLib and it works flawlessly. Yeti ___ gtk-app-devel-list mailing list gtk-app-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
Draggable Targets
I have another newbie question. I'm grateful that this list has been very indulgent of my recent questions. I want to let the user place a target (either a cross-hair or a circle) on an image and then be able to drag it to a new location. This seems like common functionality that GTK+ might directly support. How do I implement this functionality? The underlying image is in a Drawing Area which is inside a Scrolled Window. My first thought was to place a small image (of the cross-hair) on top of the image. I would need to specify the x/y offset of the target image inside the Scrolled Window, but I don't see how that is supported in GTK+, My second thought is to draw the target directly in the Drawing Area, then redraw then create the drag effect in the motion_event callback by redrawing the background where the target used to be, and drawing the target where is now. Thanks, Tim ___ gtk-app-devel-list mailing list gtk-app-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
Re: Problem swapping GtkScrolledWindow contents on the fly
Great thanks On 13 Jan 2010, at 11:05, David Nečas wrote: On Wed, Jan 13, 2010 at 10:33:07AM +, Andrew Wood wrote: Still getting strange results with this. Ive posted a skeleton app at www.simple.org/TCSAdminGTK.tar which is a single source file which can be comiled with g++ ./main.cpp `pkg-config --cflags --libs libgnome-2.0 libgnomeui-2.0 libglade-2.0` When you click one of the options on the left the contents changes on the right. At present only 'General' and 'Calls' are implemented. As you can see the first time you click one of these the widgets show correctly but the second time you click it they don't but you get no error on the console either. The guts of the issue are contained in the functions showGeneralPage() and showCallsPage() The closest explaination Ive been able to find is that the call to gtk_container_remove (GTK_CONTAINER (rightpanescrollview ),gtk_bin_get_child(GTK_BIN(rightpanescrollview))); is deleting the widgets as well as just removing them from the container, but theres no error to suggest this, and I would have thought the calls to gtk_widget_ref(callspage) or gtk_widget_ref(generalpage) would have prevented this. There must be something very simple Im overlooking here. Any ideas? Indeed, the children get removed from the container when the page is removed so the next time it's show it's empty. This is somehow caused by the widget being constructed by libglade because if you construct it manually, it does no happen. I can't help with libglade and it's already obsolete... BTW please don't use things like gtk_widget_ref() that were deprectated many years ago. Yeti __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __ ___ gtk-app-devel-list mailing list gtk-app-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
Re: Problem swapping GtkScrolledWindow contents on the fly
Just tried it with a simple vbox and label created manually and am getting exactly the same problem so its not specific to libglade David Nečas wrote: On Wed, Jan 13, 2010 at 10:33:07AM +, Andrew Wood wrote: Still getting strange results with this. Ive posted a skeleton app at www.simple.org/TCSAdminGTK.tar which is a single source file which can be comiled with g++ ./main.cpp `pkg-config --cflags --libs libgnome-2.0 libgnomeui-2.0 libglade-2.0` When you click one of the options on the left the contents changes on the right. At present only 'General' and 'Calls' are implemented. As you can see the first time you click one of these the widgets show correctly but the second time you click it they don't but you get no error on the console either. The guts of the issue are contained in the functions showGeneralPage() and showCallsPage() The closest explaination Ive been able to find is that the call to gtk_container_remove (GTK_CONTAINER (rightpanescrollview),gtk_bin_get_child(GTK_BIN(rightpanescrollview))); is deleting the widgets as well as just removing them from the container, but theres no error to suggest this, and I would have thought the calls to gtk_widget_ref(callspage) or gtk_widget_ref(generalpage) would have prevented this. There must be something very simple Im overlooking here. Any ideas? Indeed, the children get removed from the container when the page is removed so the next time it's show it's empty. This is somehow caused by the widget being constructed by libglade because if you construct it manually, it does no happen. I can't help with libglade and it's already obsolete... BTW please don't use things like gtk_widget_ref() that were deprectated many years ago. Yeti __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __ ___ gtk-app-devel-list mailing list gtk-app-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
Re: Problem swapping GtkScrolledWindow contents on the fly
On Wed, Jan 13, 2010 at 08:26:57PM +, Andrew Wood wrote:
Just tried it with a simple vbox and label created manually and am
getting exactly the same problem so its not specific to libglade
If I do this:
--- main.cpp.orig 2010-01-13 22:36:25.0 +0100
+++ main.cpp2010-01-13 22:36:38.0 +0100
@@ -116,10 +116,10 @@
g_print(Showing General Page\n);
if (generalpageinitialised==false)
{
- generalpage= glade_xml_get_widget(generalpagexml,mainvbox);
- glade_xml_signal_autoconnect(generalpagexml);
- generalpageinitialised=true;
- gtk_widget_ref(generalpage);
+generalpage = gtk_vbox_new(FALSE, 0);
+gtk_container_add(GTK_CONTAINER(generalpage),
+ gtk_label_new(Just testing...));
+g_object_ref(generalpage);
}
the General page content (i.e. the label) no longer disappears and stays
there -- and this is the behaviour I'd expect.
Yeti
P.S.: If you post a tarball it is more helpful to include a two-line
Makefile than Glade backup files and a.out that no one sane will run...
P.P.S: The code looks like a parade of obsolete and deprecated libraries
and functions (see http://live.gnome.org/LibgnomeMustDie). I hope it is
not a new project...
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