Questions tagged [signal]
Questions about signals, a kind of interprocess communication.
73
questions
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2
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Why does Ctrl + C not kill Python running in terminal?
I am trying to understand the reason why the whole Python process does not get killed when I press Ctrl + C inside and infinite loop or for that matter any Python function that I am running in ...
- 93
5
votes
2
answers
567
views
What is the signal sent when the charger is unplugged/plugged
I would like to know which signal is sent to the kernel when I unplug my laptop. I need this information to make a program to switch my power mode automatically.
I am currently on Ubuntu 23.10.
5
votes
1
answer
965
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Make gnome-terminal request user confirmation before close
When you open gnome-terminal without any options and execute a blocking command (e.g. python3, vim or cat) and then try to close the window by the close button (i.e. x button in the title bar) or some ...
- 343
4
votes
2
answers
463
views
Detect that the workspace has changed
I can change my current workspace in various ways, e.g. by clicking on some switcher widget, with some key combination, with a command in a terminal.
Is there a way to detect that the workspace has ...
- 143
4
votes
1
answer
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Ctrl-Z equivalent for GUI Programs?
I often have to run the update manager on a slow connection, and while reading my emails, I meanwhile would like to surf for 2 minutes in the web, then have the full bandwidth again for the update ...
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4
votes
3
answers
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How can I tell how long for Watchdog to wait to stop all processes?
I have a server which is monitored by Watchdog, and experiences reboots occasionally due to faulty network hardware I am unable to replace at the moment. As I read, Watchdog sends a SIGTERM to all ...
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4
votes
1
answer
9k
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How can I get yarn to use the right version of Node?
I am new to Node, JavaScript etc. and want to try messing with the code of Signal. For this I need a specific version of Node. I did this (on Ubuntu 16.04) using the following procedure:
wget https://...
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4
votes
2
answers
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Input signal out of range; Change settings to 1600 x 900
I recently installed Ubuntu 12.04 onto my HP Pavilion, in an attempt to make the desktop able to dual-boot Windows 7 and Ubuntu. I managed to get down to the last step, and finished the installation ...
- 41
3
votes
2
answers
2k
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The report belongs to a package that is not installed
I have gotten the error message "The report belongs to a package that is not installed."
Generally I would just ignore that since seemingly there is no problem except I got a crash report and then I ...
- 31
3
votes
1
answer
3k
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No SIGTERM before SIGKILL/shutdown with systemd on Ubuntu 16.04
I ran across this problem while I tried to answer a question on Stackoverflow.
On shutdown, Ubuntu 12.04 sends SIGTERM to all processes and waits at most 10 seconds before killing them with SIGKILL (...
- 171
3
votes
1
answer
1k
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remove Signal in ubuntu when you forgot how you installed it
i don't remember how i installed Signal desktop. i think i did it with ubuntu software.
the version is v1.39.6
so i removed it with all the ways i know
as if installed w/snap but it says here that ...
- 41
3
votes
1
answer
3k
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Bad WiFi reception on Asus Zenbook (Works great with Windows 7)
My WiFi reception on my Asus Zenbook (model ux31) is very weak compared to when I boot my Windows 7. I use both from the same location, and the reception on other devices (ex: my iPhone) is great.
I'm ...
- 31
3
votes
1
answer
92
views
How to identify shutdown event in linux
In my Ubuntu application, I wanted to perform certain finalization for my application before the system is being shutdown. For that, I need to identify the shutdown event in my application.
From what ...
- 365
2
votes
2
answers
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Sending SIGSTOP or SIGCONT signals graphically (similar to xkill)
Question
Do you know any tool/script to send SIGSTOP (to pause a process) or SIGCONT (to resume it) to a process by clicking on a graphical window generated by the process?
Some context
There is ...
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2
votes
1
answer
138
views
How do I make a app in Quickly and play a sound when a button is clicked in the app?
Is there anyway I can make an application in which a button made in Glade can be clicked to play a custom re-definable sound?
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2
votes
1
answer
637
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After upgrade to 16.04, wifi signal strength jumps from perfect to zero and back
I upgraded from 14.04 LTS to 16.04 LTS on HP Z230. Internet connection worked perfectly under 14.04 LTS. There were no hardware changes.
The computer connects to the router by a wireless usb device (...
- 447
2
votes
2
answers
2k
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Wifi apparently connected, but webpages won't load
I'm running the latest Ubuntu 14.04.3, and my issue today is that my Wifi connection sometimes becomes really slow, and eventually disconnects. I tried googling around to see if I can get any good ...
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2
votes
0
answers
135
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Ubuntu 16.04LTS Four monitor display issue
I've been browsing the forum trying to find a solution to my specific problem but can't find anything specific. My graphics card is the Radeon R9 380 Sapphire Nitro. I have three DVI displays, one of ...
2
votes
1
answer
312
views
Disable "System program problem detected" for segfaults in my own programs
I don't mind being notified about system programs that SEGV -- I would actually like to report those cases, so this is not a duplicate of Getting “System program problem detected” pops up regularly ...
- 1,682
2
votes
0
answers
375
views
Core only dumped upon receiving SIGQUIT
Learning about signals, I found out that calling the <stdlib.h> functionabort(void); in a C program, which roughly equals to raising a SIGABRT signal, doesn't create a core file on my Ubuntu 13....
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0
answers
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Unix Signal handling in Qt Embedded Linux [closed]
I have an application for the USB interface in Qt (Embedded Linux).
When a pen-drive is inserted, the kernel sends a signal for that and I want to recognize that signal and I want my Qt application ...
- 399
1
vote
3
answers
2k
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Is there any conflict between nohup and mpirun?
I want to start a big simulation on an ubuntu desktop computer. I have physical (not remote) access to this PC. This simulation may take some weeks. The command to start the process is:
mpirun -np ...
- 157
1
vote
1
answer
1k
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HDMI monitor not receiving signal after waking up from suspend mode
i have a problem that after I wake my ubuntu 18.04 laptop from the suspend mode, my HDMI monitor, which is set up a the primary monitor in the extended display set up, is not receiving the signal.
I ...
- 43
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vote
1
answer
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What do these Terminal Signals mean?
When I start to use a command to terminate an ongoing process, I can include a signal.
What is the difference between the signal 9 and the signal 15?
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1
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views
SIGQUIT breaks the pipe
Linux ping utility can produce some statistics on receiving SIGQUIT without terminating. It looks like this:
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=45 time=...
- 23
1
vote
1
answer
2k
views
Postgresql service stopping on its own in ubuntu server
In the postgresql log file, I found message:
startup process (PID 1886772) was terminated by signal 9: Killed
Although upon restarting service, postgresql database starts functioning normally. ...
1
vote
1
answer
56
views
What does it mean when ^\ doesn't work, but kill -9 does?
Recently, I've had a third-party program hang in a weird way. It stops taking input or output, and ^C and ^\ do nothing. kill -9 and killing the parent process do end it.
What state could the process ...
- 329
1
vote
1
answer
784
views
Signal messenger app not starting up
Over the past 2 weeks (after installing Ubuntu 18.04 from scratch) I have had problems on and off with the Signal messenger app. It sometimes doesn't start up at all. Uninstalling and reinstalling ...
- 161
1
vote
1
answer
3k
views
emit signal with custom type objects array parameter from c++ and receive in qml
I would like to emit a signal from a Qt C++ class which includes a parameter that is an array of custom objects (inherited from QObject) and receive the parameter in its qml slot, but i'm afraid it is ...
- 128
1
vote
1
answer
567
views
Keep VGA signal sending when using VGA switchbox
I am trying to mimic the VGA projector setup I had on Arch
Linux. I have three laptops connected through a VGA switchbox to an external projector. When I was using ArchLinux I used xrandr to start ...
- 21
1
vote
1
answer
566
views
Weak Wireless Signal - Atheros ar5008x drops connection
I'm dualbooting Ubuntu 12.04 with Windows Vista and while Vista handles the signal perfectly (4 or 5 bars out of 5 and never drops) Ubuntu shows 1 or 2 bars and drops the signal constantly if the ...
- 11
1
vote
1
answer
758
views
HDMI initially worked, no more and screen issues when try
Connected my System76 Lemur Ultra (Intel i5 3210M + Intel HD 4000) to my television. It showed up fine. After about 15 seconds, it abruptly disconnected for some reason with a "no signal" error on the ...
- 39
1
vote
2
answers
4k
views
Wifi signal weak while on an HP Pavilion G6
I have just installed Ubuntu 12.04 LTS along with the standard Windows 7 on my new HP pavillion g6 (AMD).
They both work fine but when I am running Ubuntu, the wifi signal strength shows low (...
- 11
1
vote
0
answers
239
views
Old version of Signal persists after update
Upon installing the latest version of Signal (6.16.0) the old and in-operable version (5.54.0) persists. Normally with other applications, the new version is installed and the old version is ...
1
vote
1
answer
315
views
Why does `/usr/bin/time` report the wrong exit status with format `%x` in case of SIGABRT?
I'm using /usr/bin/time to report information about a set of benchmarks I'm running. The interesting data points are runtime, memory usage and the exit status. This works fine except when the ...
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1
vote
1
answer
230
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Notification when some input (stdin, file, named pipe) is available? [closed]
is there some mechanism to be notified asynchronously when input from a 'file' is available?
I have a program that cyclically does its work. So far so good. But there also is a serial line and ...
- 21
1
vote
0
answers
166
views
half signal strength from wireless rtl8188ce lubuntu
I get super slow speeds (half the signal strength I get on windows) and an unstable connection. I ran this script and this is the info I get on Lubuntu 19.04 Kernel 5.0.0-29-generic.
02:00.0 Network ...
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1
vote
0
answers
43
views
Which version of Signal Desktop is legit? [duplicate]
I saw both of these in the apt sources. Since this is a secure communications app, what is the correct source to use for Ubuntu? Searching for Signal, I see:
And lower:
With these details:
Before ...
- 1,620
1
vote
0
answers
403
views
Multiple repository errors when I try any APT command after trying to install signal [duplicate]
I am currently using 18.04.
I wanted to install signal for desktop and I got this code from the site to install on Debian:
curl -s https://updates.signal.org/desktop/apt/keys.asc | sudo apt-key add ...
- 11
1
vote
0
answers
437
views
Upstart service killed by TERM signal, how to track that
I have upstart script as
description "My API API"
author "me@localhost"
env MY_API_PYTHON_HOME=/opt/services
start on runlevel [2345]
stop on runlevel [!2345]
script
mkfifo /tmp/my-api-log-fifo
...
- 143
1
vote
1
answer
3k
views
Ubuntu 16.04, hdmi monitor: no signal in login screen
My main monitor is connected over HDMI and my second one over DVI.
Both get a signal when the PC starts up, but the moment I get to the login screen the HDMI one goes dark, though it doesn't seem to ...
- 11
1
vote
0
answers
85
views
Ubuntu 16.04 immediately terminates all running programs on restart or shutdown?
When I choose restart or shutdown in Ubuntu 16.04, it immediately terminates all running applications. I'm not prompted to save open documents or anything like that - and I've lost work several times ...
- 656
1
vote
1
answer
994
views
xvfb-run hangs on trap/wait in Elastic Bamboo's Ubuntu 15.04 AMI on AWS
I'm trying to run some headless robot/Selenium tests via Elastic Bamboo using Xvfb, on Ubuntu 15.04 in AWS EC2. It works if I run Xvfb manually and then run the test...
export display=:99
Xvfb :99 -...
- 121
1
vote
0
answers
476
views
Why does sudo prevent catching SIGTSTP (Ctrl+Z)?
This program is written to catch SIGTSTP (Ctrl+Z) and bypass its normal effect, printing a message and returning to its normal operation instead of allowing its process to be suspended:
#include<...
- 11
1
vote
0
answers
71
views
The UBUNTU Graphics Catch 22
Trying to use a Live DVD to run Ubuntu 14.04.1, I get the "Monitor signal out of range" error.
I hit ctrl-alt-F1 to bring up the command line.
I do sudo nano /etc/default/grub and remove # from ...
- 11
1
vote
1
answer
2k
views
Weak wifi signal on Lenovo g series
I've just installed Ubuntu 12.10 on my Lenovo laptop and the wifi signal reception changed completely.
I had Windows installed on it first and it had no problem connecting to my home network from my ...
- 11
0
votes
1
answer
2k
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Send multiple kill signals to a process
Say I run a .sh process. And now I open a new terminal tab and I want to send signals to it, for that, I just use kill:
kill -*signal number* *pid*
right? But I want to send 13 signals at the same ...
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votes
2
answers
705
views
How to pass SIGALRM to a program which finishes execution in milliseconds?
I have a C program which computes the first n prime numbers if n is passed as an argument.
$ ./prime 5
2
3
5
7
11
The logic of the program allows me to enter into a desired function if I can give ...
- 130
0
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1
answer
2k
views
index out of range? [closed]
# load parameters file
yml = yaml.load(open(sys.argv[1]))
# imports
for pkg, functions in yml['imports'].iteritems():
stri = 'from ' + pkg + ' import ' + ','.join(functions)
exec(stri)
...
- 3
0
votes
1
answer
1k
views
How can a Qt application be notified that the user's session is ending and provide it with opportunity to save its state before being terminated?
I am writing a Qt application and have run into the following problem: when the user logs out or attempts to shut down the machine, the application is instantly terminated without providing it any ...
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