Meaning of Network Manager Dbus codes 'aa{ss}' - dbus

I am making a script to do IO to the NetworkManager over dbus. In the gnome developer docs function arguments are represented as things like 'aa{ss}' but i cannot find a description of there meaning.
Example
RouteData readable aa{sv} """<-this guy"""

Someone from the Gnome IRC was able to help me posting here in case somone else gets stuck.
https://developer.gnome.org/glib/stable/gvariant-format-strings.html
so aa{sv} means
array array dict(string,variant)

Related

Is there a way to get help for some C functions inside of vim/Neovim?

This question may be a little off topic. But I was wondering if there was a way for me to look at the descriptions of C functions using vim or neovim. Is it possible to look at their documentations by doing something like :help? This would really be helpful since I wouldn't need to lookup to my browser everytime.
I am unclear about these things:
Can :help be my friend here ?
Can I use LSPs to do something like this ?
I am using latest Neovim inside Ubunutu 20.04 in WSL. Is this helpful somehow ?
By pressing K, the keyword under the cursor is looked up using a configured keyword lookup program, the default being man. This works pretty much out of the box for the C standard library.
For C++, you might want to look at something like cppman.
Well yes, you can get the description of C functions by using a LSP (language server plugin)! Here is an image of me using clangd as my LSP:
You'd "just" need to install the LSP and start it. I don't know how familiar you're with neovim, but just in case if you don't know how to install a plugin or to be more specifique: If you don't know how you can install a LSP server, then you can do the following:
There're plenty videos how to set up a LSP-Server for your language. Here's an example.
If you don't want to set up on your own, you can pick up one of the preconfigured neovim setups (some of my friends are recommending lunarvim)
But yeah, that's it. If you have any further questions feel free to ask them in the comments.
Happy vimming c(^-^)c
Let's explain how "K" command works in more detail.
You can run external commands by prefixing them with :! command. So running man tool is as easy as
:!man <C-R><C-W>
Here <C-R><C-W> is a special key combination used to put word under cursor from text buffer down to command line.
Same for showing Vim's built-in help page
:help <C-R><C-W>
As it feels tedious to type that, Vim also defines K Normal mode command that does pretty much the same thing. Except the tool name is taken from value of an option named "keywordprg".
So doing set keywordprg=man (default for *nix systems) makes K to invoke !man tool; while set keywordprg=:help is for bultin help.
Also, the option :h 'keywordprg' is made global or local-to-buffer, so any Vim buffer is able to overwrite global setting. For example, this is already done by standard runtime for "vim" and "help" buffers, so they call ":help" instead of "man".
The problem with :!man command is that it shows "black console". It'd be nice if we could capture man's output and open it inside Vim just like a builtin help page. Then we could also apply some pretty highlighting, assign key macros and all such. This is a pretty common trick and it is already done by a standard plugin shipped with Vim/Neovim.
A command that the plugin provides is called :Man, so you can open :Man man instead of :!man man, for example. The plugin is preactivated in Neovim; for Vim you still need to source one file manually. So to make use of this plugin you'll need something like this
set keywordprg=:Man
if !has("nvim")
source $VIMRUNTIME/ftplugin/man.vim
endif
The previous answer recommending cppman is the way to go. There is no need to install a bulky language server just for the purpose of having the hover functionality. However, make sure you're caching the man pages via cppman -c. Otherwise, there will be a noticeable delay since cppman is fetching the page from cppreference.com on the fly.
If you like popups for displaying documentation, convert the uncompressed man pages (groff -t -e -mandoc -Tascii <man-page> | col -bx), and set keywordprg to your own wrapper to search for keywords according to your needs.

I cant use auxiliary functions from zephyr ( tty.h) file

I am building a project and I have the board stm nucleo_l496zg. All i want to do is to use the drivers from the board in order to communicate the board after west flash with minicom, it is a simple string transfer and response program. I am building this project with zephyr and my issue is that I cant use the functions tty_init , tty_read and tty_set_rx_buf despite that I use the proper include " #include <console/tty.h> ". The compiler returns an undefined reference to thoose three functions but in my program I am using another one function from tty.h header which is tty_set_timeout but at this function it doesnt say nothing. Though I notiched in that in here(documentation of tty.h) tty_Set_timeout is the only function that has something inside. I cant understand why I am getting that please if someone can help me let me know !
I had the same problem and I solve it by adding those lines to my .conf file:
CONFIG_SERIAL=y
CONFIG_STDOUT_CONSOLE=y
CONFIG_UART_INTERRUPT_DRIVEN=y
CONFIG_CONSOLE_SUBSYS=y
CONFIG_CONSOLE_GETCHAR=y
And don't forget to mention the file (.conf file) also in your CMakeList.txt file:
set(CONF_FILE ***.conf)
Hope that it will work with you as well

Gnome 3: Call sushi, the Nautilus quick file previewer via DBus

In Gnome 3, Nautilus has a new file previewer called Sushi. You can select a file in Nautilus, hit the spacebar and it will show a quick preview. This is very similar to what Quick Look (Preview) on OSX does. Quick Look has a command line interface that allows you to use Quick Look from inside your own application. Sushi does not appear to allow this.
It appears the only way to call sushi it via dbus. (If you know how to call it via the cmd line, even better) I found sushi's source for where it registers its dbus messages but cannot figure out how to call it.
Here's what I tried:
> qdbus org.gnome.NautilusPreviewer /org/gnome/NautilusPreviewer org.gnome.NautilusPreviewer.ShowFile /foo/bar/baz.png 0x1c00010 0
Error: org.gnome.gjs.JSError.Error
Argument 'parent' (type interface) may not be null
I'm a novice when it comes to dbus, so maybe I'm missing something obvious
> dbus-send --print-reply --dest=org.gnome.NautilusPreviewer /org/gnome/NautilusPreviewer org.gnome.NautilusPreviewer.ShowFile string:"/foo/bar/baz.png" uint32:0x1c00010 uint32:1
Error org.freedesktop.DBus.Error.InvalidArgs: Type of message, '(suu)', does not match expected type '(sib)'
Try this:
dbus-send --print-reply --dest=org.gnome.NautilusPreviewer /org/gnome/NautilusPreviewer org.gnome.NautilusPreviewer.ShowFile string:"file:///foo/bar/baz.png" int32:0 boolean:false
Your second error means you used incorrect types: you should use string, int32 and boolean (sib), not string and two unsigned integers (suu).
Also please note that you should use URI, not raw filename - just add file:// scheme prefix.
Second parameter should be xid of Window you want to show your preview over. But 0 works for me.
I am not an expert on the question and pretty novice to linux. I faced this problem too and manage to solve it by reinstalling the dbg package.
I noticed that during the upgrade to 19.10 this package add necessarily to be remove to pursue with the installation.
Once the upgrade was performed, gnome-showed the same error as mentioned #Matthew Levine in the first post. reinstall gdb solved the issue for me.

How can output be directed to specific coordinates in the linux terminal?

To be more specific, I am looking for an equivalent to the Windows API function: WriteConsoleOutputCharacter. I know this style of direct output is possible, as I have seen the behaviour used before in the time that I have used Linux. However, I am still a baby when it comes to Linux specific C libraries, and have not been able to ascertain any clues as to where I may find such functionality. Any assistance would be appreciated.
Check out ncurses library.
It allows you to create some text-based UI in terminal. It is more than you asked, but if you need more than only this one function it may be best option for you.
You can use the ANSI control sequence
Say, following will print 'ddd' string 3 lines above the prompt in bash
echo -e "\e[3Addd"
This line will put a clock in right upper conner of a terminal (from commandlinefu.com)
while sleep 1;do tput sc;tput cup 0 $(($(tput cols)-29));date;tput rc;done

nsinstall: Bad file number error on Vista

I'm attempting to build Firefox on my Windows Vista Ultimate machine. I keep getting the following error:
nsinstall: Bad file number
I've read that this error is caused because of UAC in Vista. Here are the two articles that lead me to this conclusion. https://wiki.mozilla.org/Penelope_Developer_Page#Windows_Vista and http://www.kevinbrosnan.net/mozilla-build-error-nsinstall-bad-file-number
Using the standard "Run as Administrator", I've attempted to redo my build but I get the exact same error. I also started a normal command prompt as admin and then went to the batch file in mozilla-build (start-msvc8.bat) and ran it. Still, same error at the same point.
Any other insights on how I might either get around this error or perhaps something else is causing the error?
Note: I also posted something here in the hopes to get topic-specific help but I've not heard a peep... After I posted that I found the info on nsinstall. Anyway, I prefer SO so I thought I'd try here...
Update: I've attempted to completly disable UAC to correct the problem as is suggested by cnemelkasr. I've received the exact same error. This new knowledge is making me think that a file or folder is missing... Does anyone who has experience with NSInstall know what the given error -- Bad file number -- might mean? I figure it might be referring to a file handle...
If it really is a UAC error, you can try turning off UAC altogether. I've had to do this for several packages. There are numerous places on the web to get the instructions for doing that.
http://www.petri.co.il/disable_uac_in_windows_vista.htm is one of them.
I found the answer to my question. I'm posting the answer here to share the answer with others and to close this question.
After disabling the UAC, it was suggested that the directory depth was interfering with NSInstall. I moved the folder from c:/Users/Frank/Documents/hg-repos/firefox-src-hgRepo/mozilla-fv-expirement/ to C:/mozilla-fv-expirement/. Cleaned all previous build attempts and finally redid my build (with UAC off) and I received a working debug binary.
The suggestion was posted at: mozilla.dev.builds
The "Bad file number" message in the cases I have seen, is caused by too many arguments passed to execvp (command, argv) (or similar) function. But only from some programs. An old bash, sh or a Borland/Watcom program in your PATH is an likely candidate.
So when you shorten the name of the build directory, the total size of the command line (that eventually gets passed to CreateProcess()) gets shorter. I don't think UAC has anything to do with this since I've seen this on Win-XP too. But it's a bit strange Mozilla would not use relative paths while building. I guess it uses some directory prefix value in it's makefiles (I've never tried building it).
If you look at the documentation for _execvp():
http://msdn.microsoft.com/en-us/library/3xw6zy53.aspx
E2BIG is one of the possible errno values:
The space required for the arguments and environment settings exceeds 32 KB.
Now, here is the strange part.
Fact 1:
On Visual-C/MingW (any version), strerror(EBADF) doesn't return "Bad file number" .
(it return "Bad file descriptor").
Fact 2:
On Borland's CBuilder 5.6 and Watcom 1.9 (these do not use the MSVC runtime), strerror(EBADF) does indeed return "Bad file number".
Theory:
Is possible that Borland, Watcom (and other CRTs too?) mixes up the meaning of E2BIG and EBADF. Did that make any sense? Someone please correct me if you have a better theory.
I'm a bit confused myself...
Conclusion: Either shorten the size of your environment (easiest) or shorten the command-line (not always easy).
--gv

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