I am trying to get a hang of vala. It is an interesting project and I am trying to build an app for Budgie.
Unfortunately, the documentation seems not too complete.
I am trying to build this simple app from here , but every time I try to compile using meson, I always get the error message:
The symbol `GMenu' could not be found
I figure this is due to a missing library, and tried installing libgnome-menu-3-dev, but it’s already and installed and didn’t solve the issue.
Any hint?
you mentioned you are using meson - what is your meson.build file?
That’s the file:
project('com.github.rainer' , 'vala' , 'c')
executable (
meson.project_name(),
'Window.vala',
'Application.vala',
dependencies: [
dependency('gtk+-3.0')
],
install: true
)the example gave the direct compilation as:
valac --pkg gio-unix-2.0 --pkg libgnome-menu -o gnomemenusample GnomeMenuSample.vala -X "-DGMENU_I_KNOW_THIS_IS_UNSTABLE"
So you’ll need to add each of the --pkg entries as part of the meson file - I’m not sure dependencies is the correct thing - worth a try I suppose - guessing should be vala_args:
project('com.github.rainer' , 'vala' , 'c')
executable (
meson.project_name(),
'Window.vala',
'Application.vala',
vala_args: [
'--pkg', 'gtk+-3.0',
'--pkg', 'libgnome-menu-3.0',
'--pkg', 'gio-unix-2.0',
],
install: true
)
This bit will need to be added to meson: “-DGMENU_I_KNOW_THIS_IS_UNSTABLE” which is a c_arg
i.e.
project('com.github.rainer' , 'vala' , 'c')
executable (
meson.project_name(),
'Window.vala',
'Application.vala',
vala_args: [
'--pkg', 'gtk+-3.0',
'--pkg', 'libgnome-menu-3.0',
'--pkg', 'gio-unix-2.0',
],
c_args: [
'-DGMENU_I_KNOW_THIS_IS_UNSTABLE',
],
install: true
)
… doing all this from memory … so probably needs a bit of fiddling to get the syntax etc right.
One step closer; there is still one small issue, though:
../GnomeMenuSample.vala:9.18-9.31: error: The type name `GMenu.TreeItem' could not be found
foreach (GMenu.TreeItem item in root.get_contents ()) {
Compiling with the command indicated in the tutorial :
valac --pkg gio-unix-2.0 --pkg libgnome-menu -o gnomemenusample GnomeMenuSample.vala -X "-DGMENU_I_KNOW_THIS_IS_UNSTABLE"
throws the following error:
fatal error: gnome-menus/gmenu-tree.h: No such file or directory #include <gnome-menus/gmenu-tree.h>hmm … looks like that is an out of date example
get_root_directory() returns a TreeDirectory
Think now you have to use “get_tree” on that return value which returns a Tree … etc
There doesn’t appear to be a TreeItem any more
This is how budgie menu’s work https://github.com/solus-project/budgie-desktop/blob/master/src/applets/budgie-menu/BudgieMenuWindow.vala#L117
Thanks for looking into this, David. I see what I can do from here. I on the Slingswarm application. But your advice was very helpful.
I am starting to get used to Vala and like it.
Working my way through Vala. I am still trying to get the Slingshot App to work, but ran into another compiling issue that I can’t figure out.
The are zillions of answers on the net for Java, but only few threads for Vala.
When I try to compile, I get the error message:
/usr/bin/ld: /lib/x86_64-linux-gnu/libm.so.6: error adding symbols:
DSO missing from command line collect2:
error: ld returned 1 exit status
I found an answer on StackOverFlow, that recommends to install the missing library. Searching on Ubuntu Packages, the closest package in name I found, was
libm17n-dev
what I installed and added to the meson build file, what now looks like this:
executable(
meson.project_name(),
'./SlingshotWindow.vala',
'./Frontend/Widgets/Utilities.vala',
'./Frontend/Widgets/Color.vala',
'./Backend/GMenuEntries.vala',
'./Frontend/Widgets/CompositedWindow.vala',
'./Frontend/Widgets/Searchbar.vala',
'./Frontend/Widgets/AppItem.vala',
'./Frontend/Widgets/Indicators.vala',
dependencies: [
dependency('gtk+-3.0'),
dependency('gee-0.8'),
dependency('gio-unix-2.0'),
dependency('libgnome-menu-3.0'),
#dependency('libm17n-dev')
],
c_args: [
'-DGMENU_I_KNOW_THIS_IS_UNSTABLE',
],
install: true
)
Compiling that returns:
Dependency libm17n-dev found: NO (tried pkgconfig and cmake)
meson.build:5:4: ERROR: Dependency "libm17n-dev" not found,
tried pkgconfig and cmake
sudo apt install libm17n-dev
gives:
libm17n-dev is already the newest version (1.8.0-2)
Am I on the right track?
That’s a linker error - basically your meson.build needs to link with “-lm” in your c-arguments statement
e.g.
BudgieShowTimeCArgs = [
'-include',
'config.h',
'-lm',
'-DWNCK_I_KNOW_THIS_IS_UNSTABLE'
]
Compiling you entire solution returns:
meson.build:5:4: ERROR:
All keyword arguments must be after positional arguments.
This solution:
c_args: [
'-include',
'config.h',
'-lm',
'-DWNCK_I_KNOW_THIS_IS_UNSTABLE'
],
returns:
fatal error: config.h: No such file or directory
And this :
c_args: [
'-include',
#'config.h',
'-lm',
'-DWNCK_I_KNOW_THIS_IS_UNSTABLE'
],
returns:
cc1: fatal error: -Wl,--start-group: No such file or directorythat was just an example - to take your bit of code and amending it:
c_args: [
'-DGMENU_I_KNOW_THIS_IS_UNSTABLE',
'-lm'
],
Compiling that returns:
/usr/bin/ld: /lib/x86_64-linux-gnu/libm.so.6: error adding symbols:
DSO missing from command lineYour dependencies also need to say it needs the math module:
dependencies: [
dependency('gtk+-3.0'),
dependency('gee-0.8'),
dependency('gio-unix-2.0'),
dependency('libgnome-menu-3.0'),
meson.get_compiler('c').find_library('m', required: false)
],Cool … compiling went ok, thanks for the aid and the patience.
Running the app, I get an error:
Segmentation fault (core dumped)
Is this related to the meson compiler?
Very unlikely.
This is likely to be a coding issue. You will need to add things like
message('have you got here yet');
Throughout bits if the code you suspect could be at issue until you narrow down the problem area
Thanks, David. A big project like Slingshot is maybe not the best to start with getting into Vala, but I just go for it.
Have a pleasant day.