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:
Code: #include <unistd.h>
#include <sys/types.h>
#include <stdio.h>
#include <signal.h>
typedef struct data
[Code]...
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:
View 1 Replies View RelatedI am working on tracing the signal handling mechanism in linux kernel internallly. For that, i build the kernel. Now, i want to trace the signal handling mechanism in the old kernel. I got to about SYSLOG and PRINTK for this. But, how to use these tools exactly in tracing the handling of signals internally ?. Is, there any tool similar to backtrace to do that?. How the call flow is done internally ?
View 1 Replies View RelatedI wrote some code in c, using pthread (I configured the linker and compiler in eclipse IDE first).
Code: #include <pthread.h>
#include "starter.h"
#include "UI.h"
Page* MM;
[Code]....
I have faced a problem with my code (a small tcp server). After the thread returns, the memory not decreases, but when a new connection is made, memory not increases and the new connection initialize a new thread with a same thread id of the previous thread. When two connections are made at same time, two thread ids are created and when the respective threads returns the memory not decreases. The Valgrind indicates that not memory leak occurs, the pointers are released. Indeed, more memory are allocate when new thread id is created. i used gcc and debian.
[Code]....
I have an application that has pretty large memory profile. The general program flow is as follows:
Code:
main:
do 10 times:
[code]....
im writing a cross-platform software (linux/solaris/mac/bsd) so i was wondering, how portable is pthread library? out of 10 linux distros, how many will have it by default? and does it exists on mac/solaris/bsd by default? or user will have to install it?
View 6 Replies View RelatedI want to suspend/resume a thread. The library I am using is pthread.h.I am also running my application on linux.Is there any function in pthread. let me suspend a thread temporary?I have read a document in which it was mentioned thatthread does not support suspend/resume
View 4 Replies View RelatedI'm trying to figure out how pthreads are mapped from the compiler to the Linux kernel. The pthread prototypes are found in a compiler header file (pthread.h), yet the kernel would be responsible for scheduling the threads. So, how does the compiler resolve the pthread symbols at compile time?
View 1 Replies View RelatedI am wondering if pthread could make that a single thread keeps the "mutex" all the time if the time it remains unlocked is very small.
thread1
{
while (1)
{
lock; do_task(); unlock();
[code]...
I experiment the thread2 never getting access to the mutex and never printing the nice message. I would expect that once thread2 calls "lock", it would get the mutex as soon as thread1 calls unlock() but it does not seem to be the case. If I add a sleep of some microseconds (100) in thread1 after unlocking the mutex, it solves the problem.
Does anyone know if this behaviour is normal? Is there a way to configure my mutex so that thread2 receives it when unlocked?I use
pthread_mutexattr_settype(&att, PTHREAD_MUTEX_RECURSIVE_NP);
pthread_mutex_init(&handle, &att);
to create my mutex. I am running ubuntu 9.04
I am working on a large program in C to run on Puppy Linux. I have multiple pthreads running. I want to be able to set the pthread SCHED_POLICY and priority in my program but I want a user to be able to run the program without root privilege.
Using a sticky bit and root ownership gives the user too much power because they will be able to write and compile their own scripts. Is there a way to use 'sudo' when I set the thread parameters from my program or something like this?
I have to compute prime numbers with threads in C. So I choose the algorithm "Sieve of Eratosthenes" and I tried to create 2 threads, but I don't know how to optimize my computing function with threads I beg for help. This is my function:
[Code]...
but it seems like the both of the threads are calculating the same function twice? Is it possible to be optimized or not?
I'm just starting out on a project relating to web search, to be done in C++. Which library should I use to help with downloading web pages into memory so that I can process them? The big thing is I want to be able to download the pages into variables/structures without actually putting them onto the hard disk.I googled and saw libcurl, but I was confused by some of the examples and wondering if this was really what I wanted.
View 2 Replies View RelatedI wonder how error handling is done in C in real applications, by returning a error code when something goes wrong, or by using setjmp and longjmp, or something else?
View 10 Replies View RelatedI'm building a simple(?) socket server using threads to serve up a few requests. The spec is such that I have to listen to three ports at once, so I decided to use pthread to create three separate threads that would wait for connections, then spawn new threads to handle them.
The problem is that when I do this, for some reason the program never enters the wait loop and instead terminates (All three threads did get created since the messages get printed properly.) It gets to the line which prints "???", but not the line after the accept() call.I don't see an open port when I check for one either so I'm 99% sure they're terminating.Basically I have a main() method which has three calls to pthread_create, which should result in three threads being run that all wait for connections (listenOnPort). After each thread creation I print some info to make sure it's actually being created.
By the way, when I just run listenOnPortwithout threading, the server appears to enter the loop correctly and seems to be waiting for requests. It's only when I run the functions as threads that the problem seems to happen.The source is attached below. Any help will be appreciated. Much of the code is borrowed from a website (I can't post it because I am new here.) You need not worry about the handler_ methods because those are just methods that are run by the threads themselves.
Also--the original source was in C and I changed it to C++. Should I just use C?
server.h Code: /*
* server.h
[code]....
I writed Quote:
#!/usr/bin/perl -w
use Error qw(:try);
try {
[code]....
I found, in bash, something similar to 'try/except' in python. I've been using something like this:
Code:
if ! 'command';then
echo 'damn, there was an error'
[code]....
During my read, "Code Complete",the author described the different ways of handling the ADT interface.He has wrote this passage:
Quote:
Option 2: Explicitly provide the data used by the ADT services. In this approach, you declare the data that the ADT uses within each routine that uses an ADT service. In other words, you create a Font data type that you pass to each of the ADT service routines. You must design the ADT service routines so that they use the Font data that's passed to them each time they're called. The client code doesn't need a font ID if you use this approach because it keeps track of the font data itself. (Even though the data is available directly from the Font data type, you should access it only with the ADT service routines.This is called keeping the structure "closed.") The advantage of this approach is that the ADT service routines don't have to look up font information based on a font ID. The disadvantage is that it exposes font data to the rest of the program, which increases the likelihood that client code will make use of the
ADT's implementation details that should have remained hidden within the ADT.
The problem is that it is a bit subtle in terms of coding for me. Can anybody give more concrete example, in working codes, especially in Java?
i have an application that launches several pthreads, i know that the default size used by Linux is 8Mb for each pthread. However i would like to optimize the total memory usage by my application by decreasing the default stack size of each pthread to the needed resources. My questions:
- Are there any rules to set the pthread stack size.
- How to compute the memory needed by each thread.
- Is the malloc call inside a thread counted from the stack size of the same pthread?
I have a script that connects to a windows server, downloads a file, appends to it and then re-uploads the updated file. I want to implement error handling. An email is to be generated indicating whether there was an error or not. This email should include all standard and error output as a body. The current script looks something like this:
Code:
function Email_ServerSupport {
for time in once; do
echo "Subject: Billing - smb copy to accounting" $1
cat /tmp/smbx
cat /tmp/smbxerr
done | mail $EMAILADDR
}
/usr/bin/cp /dev/null /tmp/smbx
/usr/bin/cp /dev/null /tmp/smbxerr
cd /tmp
/usr/sfw/bin/smbclient $LOCATION -A $AUTHFILE >>/tmp/smbx <<EOF
get $OUTFILE
exit
EOF
cat $INFILE >> $OUTFILE
/usr/sfw/bin/smbxclient $LOCATION -A $AUTHFILE >>/tmp/smbx <<EOF
put $OUTFILE
cat /tmp/smbx | grep -v "Domain" | grep -v "putting file" | grep -v "getting file" >> /tmp/smbxerr
if [ -s /tmp/smbxerr ]; then
Email_ServerSupport " ERROR"
exit
else
echo "Transfer successful."
Email_ServerSupport " SUCCESS"
fi
The reason for the grep -v's is because, from my understanding, when using smbclient, ALL output goes to stdout, even errors. For this reason, I need to filter out lines including "domain" "putting file" or "getting file", all of which aren't errors. The problem is that even though the script seems to catch errors successfully now and then, the success email ends up blank (/tmp/smbx is somehow empty). I'm also worried it could miss possible errors I haven't tested. I'm thinking it has to do with the way "EOF" functions. Is there any way to capture output from the "put" and "get" commands? I can't simply redirect the output, can I?
To parse several XML documents I'm using libxml++. I do programming for linux angstrom-armv5te. Because compiling libxml++ for this distribution and platform was impossible, I simply included the library to my project, which workes fine. Unfortunately I'm not able not use the exception handing which effects that a simple error inside a documents makes my whole program crash. This should not happen.
Is there a way to check the documents validity before parsing or better active the exception handling for doing this.
i had a problem with the find command in bash (which i deem is close enough to a promming language, if not please move this thread :P). i tried to reduce the command to the problem. i want the backticks, or $() for that matter; to be evaluated by -exec of find, not by bash. is that a caveat of find?
Code:
$ find testd -exec echo `basename {}` ; #confused me
test
test/a
test/b
[code]...
edit: i found out whats causing this. `basename {}` gets evaluated by bash before find is invoked, returns {} and `find . -exec echo {} ;" is run. now my question is, how to escape this eveluation from happening before.
I have this little shell script which copies file names taken from inputfile:
Code:
while read line; do
cp -i $line something
[code]...
i have some perl codes for using ldap,but i don't know why don't work any error handling When i use msg->code for sample. an example:
[Code],,,,
In this case,if $msg->code return zero(or null) every thing work correctly but if it not zero don't give any message(eg."error result").What is problem?
I have a system setup script for my Slackware installations that pulls all packages and source files from another machine and sets everything up to be identical between machines. The script works as expected but make it entirely unattended. How do I make the bash script deal with automatically selecting "Yes" for, for example "Install x(Yes/No): " when prompted by a make file?
View 3 Replies View RelatedI 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":
Code:
vd = totem_object.get_video_widget()
vd.connect("clicked", vd.hide)
[code]....
I've been trying to understand pthread in C a little better. So I made a simple program that takes in a string from the command line and creates a thread to print the string. I've looked online and copied the basic concepts but there are something things I'm confused about. The programs works just fine, but I have questions. Here's what I have so far.
[Code]....
One thing I'd like to know is why the 3rd argument in the pthread_create function which is my SendMessage function needs to be typecasted to a void pointer and then send the address of the function. Also as for the 4th argument, I would see typecasting to void pointer in some of the pthread examples I saw online, but in my case I'm passing a char pointer, would this be correct? In which case would I ever want to pass a void pointer?
Do I need a pthread_exit(NULL) in my main and in the SendMessage function? If so, why? I added the sleep() function so that I could let the pthread_exit function in my SendMessage function execute first. I simply saw that the online examples on pthread had pthread_exit() in both locations.
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 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:
Code:
#include <TCPServerSocket.hpp>
#include <string>
[code]...
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
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