Programming :: Sequencing With Raising A Signal Method?
Mar 4, 2010
I was trying to program using fork(). The objective of this code is to
1. I am activating a process A - SubSuctionMotors.
2. Process A is going to stop with either of this condition
a) Switch is activated - swret=1
b) Time allowed has expired
3. Stop the process A.
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1. We purposely force the switch to be inactive to test the child process (timer), whether after 2 seconds the motor stop. It turns out to be successful in first few attempts. After some while, the program hang, nothing is executed anymore and the program is not exit or terminated. What can cause the program to hang?
2. We tried to stop motor by switch activation (if the switch is to be successfully activated, the time it takes will always be shorter than the timer allowed time). However, the program did not seems like noticing the switch has been activated, and it just stop the motor according to timer. Why it behave this way?
I want that I click with the mouse on the video, it paused.I notice that there is "BaconVideoWidget" which I guess is the video rendering widget but it don't have signal named "clicked":
I need to ftp all of my Linux server files & folders through FTP Pro . But I can just login as /home/www user and I cannot login as super user that is suitable for my case (as I want to see all of the files) . how can I raise the priority of ftp such that FTP Pro can login to my Linux server as root user ?
I am not a programmer. But I feel safe enough to edit a file (afteracking it up of course.)I am using Arch with Enlightenment (E17.) I installed fwbuilder. Now when I click on the tutorial button it would not start my browser at all. The terminal gave this error;
Code: /usr/bin/xdg-open: line 478: firefox: command not found /usr/bin/xdg-open: line 478: mozilla: command not found
I want to encrypt a text using rsa encryption method. I did it using command openssl but i want it using my library api, the library api is as, int rsa_calc (unsigned char * msg, unsigned char * mod, int count, int exp, unsigned char result); I can't understand how i input public key (.pem file) and what will be the modulus (unsigned char * mod) and exponent (int exp) for any text.Is there any kind of formula to calculate modulus and exponent of the text.
I wish to know that which gcc release version had support on ARM 9 multicore system by using pthread library for its parallelizing method on ecos rtos.I assume that the compiler that support the single ARM 9 processor will surely compile its multicore version also.But i need a clarification about it.It is good if you give a article or provide a suitable link on the ARM multicore programming and its compilation method
I wrote a code for login verification..I got output with GET. But I need output with POST since it is more secure. Any error in my code.
javascript code: var xml; function verifyusernamepasswd(pass) { //pass is password that will be passed as parameter xml=new XMLHttpRequest(); var url="http://localhost/loginvalidate.php"; var para="q="+username+"&p="+pass;//username is global xml.setRequestHeader("Content-type", "application/x-www-form-urlencoded"); xml.setRequestHeader("Content-length", para.length); xml.setRequestHeader("Connection", "close"); xml.open("POST",url,true); xml.onreadystatechange=statechanged1; xml.send(para); } .....
The verification does not return anything, cos my alert is not displayed at all.
I'm doing the shell history audit logging using syslog to gather the command history. I'm using this well publicized method using trap and logger:
declare -r REAL_LOGNAME=`/usr/bin/who am i | cut -d" " -f1` function log2syslog { declare command command=`fc -ln -0` logger -p local1.notice -t bash -i ": $REAL_LOGNAME as $LOGNAME :$command" } trap log2syslog DEBUG TERM
The problem is that the trap on DEBUG will catch the next to last command executed (by virtue of the "fc" command) which is not the current command executed. TERM will catch that "next to last" command on exit, thus completing the logging of each command executed during that session.
However, CTL+D doesn't seem to emit a SIGTERM signal. What signal is actually being emitted and can it be trapped? I guess another question would be whether there is a way to trap history after command line execution? Moving to Bash 4.1 isn't possible in our "supported" multi-platform environment
I have created a pthread, and installed a signal handler inside that, same way as we do in main( ) function. The thread's signal handler is a separate function. Surprisingly, it is not working, that is the thread's signal handler is not able to catch signals. Here is the code:
I have a Socket library, written in C++, in which the method used to send data never has the opportunity to handle an errno of SIGPIPE. Thus I thought perhaps I should setup a signal handler to receive the signal, but this too is not being called.Is there something that I am missing or doing that is completely wrong? Below is the relevant code. Note that a SIGPIPE signal is generated when the Server is unable to send data to the Client (e.g. the client has terminated).Server code:
When adding repositories, I ran up past the default apt cache limit of 25165824. I found a couple of sources - one that treats apt.conf.d as an individual file, and another that treated it as a folder - which my system does.
Following those guidelines, I went into /etc/apt/apt.conf.d/debconf70 to add a line of code that sets the default to 2x and 4x that limit, and... well, apt doesn't seem to recognize the difference.
Here's the code I added at the end:
So, is there somewhere else that I need to change things? Am I completely off on this? I found a year-old thread on this error in the ubuntu forums, where a gentleman who is now a member of the staff simply suggested to the op "take out that debian repository you listed". It kinda negated the premise for me, you know? I'm kinda hoping there's more that I can do.
Is it possible to connect a signal handler to a variable?So when the variable changes the signal handler is called.I have a vector containing strings which i want to parse when there are one or more available strings in the vector
I have a signal handler in my tool, which is registered and used between some particular interval (i am using timer). Now this signal handler should NOT allow any other handler to be registered or invoked after this handler is once registered. Is there any way to accomplish this?
I am writing a bash script where I need standard Input should be saved in a file and should be terminated by passing CTRL+D signal. Any clue how can I do that in bash script.
e.g. Enter one line at a time Press CTRL+D to finish
But unable to catch the SIGTERM signal if I do shutdown, as man pages says shutdown genrates the SIGTERM and SIGKILL signals, but we cant handle the SIGKILL signal. My code is working fine if I genrate the SIGTERM signal by Kill command, and also for SIGINT signgal genrated from the CTRL+c key.
Here is my code:
/* Example of using sigaction() to setup a signal handler with 3 arguments * including siginfo_t. */ #include <stdio.h> #include <unistd.h> #include <signal.h> #include <string.h>
I'm just beginning to program with GTK+, and I'm facing this issue: I want to inhibit a signal emission inside one and only one function. I've down cut my code into the smallest example I can to show you what I want to do:The "Emitter" contains a "GtkSpinBox" and it relays the "value-changed" signal, it's header:
I just wonder if anyone can give some hint regarding my problem. I have a server based on RHEL 4.4.What I have noticed is that server load average is raising in approx. 7-10 days by approx. 7, even if has very low CPU utilization, memory utilization on approx 80% and low on I/O stats.Linux apollo 2.6.9-67.ELsmp #1 SMP Wed Nov 7 13:58:04 EST 2007 i686 i686 i386 GNU/Linux
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Server is used as compilator / build machine to build aplication from source code stored in IBM Rational clearcase envinronment, and as a test server to test those builds with network equipment. Does anyone can tell what could be causing this behaviour?
Basically I'm intending to write serial RX signal handler.Application receives defined packages of data over serial which contains header and payload. Handler should analyse incoming stream and upon detection of header (header is 6B in length) switches to receive payload of length defined in header, then after receiving full message packs it and sends to application for handling.Problem I'm facing is that at random moments in signal I receive errors that "Resource temporarily unavailable" while reading from ttyOx device and I see that sometimes I miss incoming data.Also is it possible that if while I'm handling signal one more signal arrives and it is started to be handled parallel? If it is, what are the ways to prevent it? So I would be sure that no more signals will fire on same peripheral until I will finish handling what I have on my hands now.
Serial open and init: Code: Select allint open_port(int port_nr) { int fd; /* File descriptor for the port */ switch (port_nr) { case 1: fd = open("/dev/ttyO1", O_RDWR | O_NOCTTY | O_NDELAY); break;
locking mutex (phtread_t type) in a signal handler function (installed by function signal()) for Linux. It seems that if the mutex has been previously locked by another thread outside the signal handler function and then the signal handler function tries to lock it, the whole process hangs.
I'm new to Unix and every signal handler algorithm I've seen is more or less a copy of what I'm trying to do.[URL] designing a signal handler with sigwait in UNIX?
I have a problem with the last point of some homework I have for an OS class. I need the program to print the pid upon execution, then for 10 seconds react to SIGUSR1, SIGUSR2 and SIGTERM. If either USR1 or USR2 is received, the 10 seconds are reset. Some of the functions I'm told to use are alarm(), pause() and signal(). The nicest way I found was to handle SIGUSR1, SIGUSR2 and SIGALRM in the parent process, with SIGALRM killing the child (with a SIGTERM). In the child a pause() (or for(; pause() would be enough for it to be alive until killed from the SIGALRM handler in the parent.
What I found is that I can't just do a wait() in the parent process, waiting for the child to be killed, since whenever the parent receives a SIGUSR1 or SIGUSR2, the right handler is called but the child exits nicely. I tried blocking/ignoring those signals in the child, since the default behaviour for SIGUSR1 and SIGUSR2 is to terminate the process, but the result is the same. The only way I could do it is using a waitpid() within a do { } while(!WIFSIGNALED(status)) since when the child gets killed with the parent's kill(), it's WIFSIGNALED, whereas when it exits after the parent handles a SIGUSR1/2, it's WIFEXITED.
P.S. What I'm doing to achieve the expected 10s window is calling alarm(10) in the parent process and again within the SIGUSR1/2 handlers. In the SIGALRM handler I kill the child and within the child I simply do a for(; pause()
I am using an imx27 and have a timer set up for 100 ms and a loop to count the pulses while the timer has not expired. I get about 90 % reliable results but every once in a while i get one that is out to lunch. I am reading in a signal that is about 500khz and counting on an transition. I usually get around 85k count. But i will randomly get a 50k count.
In a single main() function,so need signal handling. Use Posix Message Queue IPC mechanism , can ignore the priority and other linked list message,to implement the scenario:
