Programming :: Is Popen Thread Safe Via Pthreads?
Sep 17, 2010I don't seem to find a conclusive answer to this one...."Is popen thread safe via pthreads?"
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Programming :: How To Bind Thread To Specific Thread In Multithread Application?
Dec 25, 2010I am going to use "pthread_setaffinity_np" to bind a thread to a specific core. My application has two threads. I have used mutex to assign a specific id to each thread and then bind that thread to a core different from another core. but it seems that the os assigns both thread to one core.What should I do to bind each thread to a specific core?
View 4 Replies View RelatedProgramming :: How To Extract Output Ulimit Under Popen
Jan 30, 2011A strange question, I guess. I'm running processes called from a c main program. The calling is performed (for now) as: FILE * res=popen(ulimit -t 1; prg args); So I can read the stdout of the process as a file and analyze it. The time limit is important for me.
2 questions:
1. How do I get to know if the process terminated on its own or by the ulimit?
2. How do I limit to times that are less than 1 sec (I have many of those).
I know that setrlimit exists, just before I change my whole approach I wanted to see if I can deal with these things from the outside.
Programming :: Segmentation Fault With Popen And Fgetws?
Dec 12, 2010Is it ok to read a process output with fgetws? I get segmentation fault when I try that.
Code:
#include <iostream>
#include <cstdio>
int main()
{
wchar_t line[4096];
[Code]...
I can read the output from the process if I use fgets instead of fgetws.But I am getting special characters in the output for some commands, that is why I wanted to try with fgetws.
Programming :: Learn Basic C++ - Implement Something Using System() Or Popen() Without Success
Jul 21, 2010I've got a (very) simple perl xinetd server that I'd like to port to C++. implement something similar using system() or popen() without success.
[code]...
Programming :: Preemption And Scheduling Of Pthreads
Feb 10, 2010i think we can simulate preemption by using 2 different priority thread, am i true? I just try these scenario :
1. Create Thread A with priority 99 , SCHED_FIFO..
2. Create Thread B with priority 4 , SCHED_FIFO
Thread A started and doing some busy work.. I guess that Thread B wouldn't start until thread A finished, but I get thread B can run before Thread A finished (It just like a common task switching).. I'm sure my 2 thread has right priority. and if thread B is doing some work and if i yield it to thread A, it should preempt it but this doesnt happen, do someone kno wats happening?
Programming :: Suspend Pthreads Without Condition
Jun 29, 2010I just started with Pthreads and don't really know much about it. I want to suspend pthreads but apparently, there is no such function as pthread_suspend. but I don't understand why we need both mutex and condition to suspend and resume a pthread. Is it possible to suspend and resume it without using conditions?
View 1 Replies View RelatedProgramming :: Pthreads Return Value Valid Or Not
Jun 14, 2010I have confusion regarding pthreads return value. All in short, is the is a valid return value ?
[source]
void * myThrRoutine(void *arg)
{
struct myStruct **myst = (struct myStruct**) arg;
cout<<"In thread "<<(*myst)->var<<(*myst)->msg<<endl;
int x = 20;
pthread_exit((void*)x);
}
[/source]
This seems to work fine on pthread_join , but I want to ensure it is not by chance.
Programming :: Segfault In Program Using Pthreads
Mar 16, 2010I am trying to write a peer to peer application in C++ using pthreads library. There are few types of nodes that run in the program. The 'beacon' nodes form the core of the network. The ordinary nodes 'join' the network by sending join requests to the beacon node. So, my program runs till the join requests and responses are received. When I try to 'connect' using connect function from the socket library, I get a segfault. I am not sure if the segfault occurs for the connect function, because sometimes the program just runs to completion. It could be an issue related to threads or memory allocation.
When I run gdb, it shows me the following:
Code:
(gdb) run b2-n00.ini
Starting program: sv_node b2-n00.ini
servant:12600> [New LWP 1]
[New LWP 2]
[New LWP 3]
[New LWP 4]
[New LWP 5]
[New LWP 6]
Before Exiting[LWP 1 exited]
procfs: fetch_registers, get_gregs line 3768, /proc/23952/lwp/1: No such file or directory.
Programming :: Using Lock In OpenMP And Pthreads
Apr 14, 2011I have a program that uses both Pthreads and OpenMP. Basically, 2 threads (Thread A and B) are created using Pthreads to do work, and in Thread A, OpenMP is used to parallelize a for loop.If I have a global variable that is accessed by the OpenMP threads and also Thread B, can I use the lock in OpenMP to ensure I have no race conditions?
View 2 Replies View RelatedProgramming :: Related To Pthreads And Timers In POSIX Standard
Feb 17, 2010I have created two threads:
Thread 1 and thread 2
In the main thread, i have put up a timer which generates a signal periodically when it expires, which reults in execution going to signal catcher function.when this function is invoked, under certain condition it goes to thread 1 and under another condition it goes to thread 2. The problem lies here that when it goes to thread2,i have a loop to process but it doesnt come out of the loop and hence from thread2, even though timer has expired.
Programming :: Unix Programming - Single Thread Server Can Support Exactly 2 Clients At Once
Sep 28, 2010A simple TCP based chat server could allow users to use any TCP client (telnet, for example) to communicate with each other. For this question you should consider a single process, single thread server that can support exactly 2 clients at once, the server simply forwards whatever is sent from one client to the other (in both directions). Your server must not insist on any specific ordering of messages as soon as something is sent from one client it is immediately forwarded to the other client. As soon as either client terminates the connection the server can exit
View 4 Replies View RelatedProgramming :: Quickest Way To Get Thread Id
Jun 24, 2010What is the quickest way to get the thread id(tid) of the current thread in linux? Specifically I use fedora 13. ...and I am talking about inside a C++ program.
View 2 Replies View RelatedProgramming :: Determine What CPU Thread Is On?
Jul 2, 2010Is there a library/system call that will return to me what CPU core a thread of execution is running on? I've looked for a bit on the net already and also in /usr/include and couldn't find one.
getcpu() and sched_getcpu() are two that I found, but when I include the appropriate header files (linux/getcpu.h, and sys/sched.h respectively), gcc says getcpu.h doesn't exist and the linker complains it cannot find the implementation in sched.h.
I'm sure I'm doing something really stupid or overthinking...
What I am doing is running an OpenMP application and specifying a list of cpu cores to run on with GOMP_CPU_AFFINITY. I want to make sure that each core is getting the same number of threads.
**UPDATE**
It seems that this code works, but only with glibc >= 2.6, and my machine has 2.5:
Code:
#define _GNU_SOURCE
#include <stdio.h>
#include <utmpx.h>
int main( void )
[Code].....
Programming :: Thread Scheduling And Signalling
Mar 23, 2010I have a program which is uses sigaction to register for a SIGIO signal (for incoming data on a fd) with an appropriate event handler. I also create a new detached thread 'B' that does some work with the received data. Normally the thread B runs properly. But when my event handler is called (because a there is new incoming data), after the event is handled, the thread B is not called immediately. There is a noticeable delay of the order of many seconds before it is scheduled again .During this delay, my program is doing nothing.
What am i doing wrong? Is there someway i can run thread B as soon as the event is handled (and assuming no other work is to be carried out)?
Programming :: Close The Thread Externally?
Aug 11, 2010i created one thread in main(). I have while in thread function.
I want close the thread in main after some time. How can i close it.
Programming :: How To Make Thread Nicer?
Feb 16, 2010Kernel: 2.6.24.2
System: Embedded System
I have a process and two threads running in it. Thread1 is my GUI-Thread (using FLTK) and Thread2 is running at the first 10 sec. after start.Now, I would like to make Thread2 "nicer" to Thread1, because otherwise GUI stucks sometimes. But I didn't find a solution.Is it possible to define the "niceness" of threads inside a process (to each other)? And if so, how do I have to do this?
Programming :: Passing Data To A New Thread?
Feb 11, 2011I have to launch a new thread from my existing main program and pass data to it.
For now the data is simply a string value.
How I go about passing data to a new thread while it is running.
Programming :: Thread Stack Using Pthread_attr_setstackaddr()?
Sep 22, 2010When I set the stack base address of the child thread using the POSIX library function "pthread_attr_setstackaddr()", I am unable to access the memory contents of its parent. The data-structures that are created on the HEAP of its parent using malloc() are either getting destroyed or unaccessible when moving to the context of the child thread. These data-structures are being passed as an argument to the child thread.Even if I make these variables global then also it is not working.pthread_attr_setstacksize(tattr, ...);stackbase = (void *) malloc(...);pthread_attr_setstackaddr(tattr, stackbase);But when I create the child thread without setting its stack base address using that pthread_attr_setstackaddr(), then it is able to access the parent's memory contents.
View 1 Replies View RelatedProgramming :: Get List Of Thread In Running Process?
Jan 27, 2010How to get list of threads of a process using C code in Linux?
View 6 Replies View RelatedProgramming :: Counting Context Switches On Thread?
Jun 10, 2010I have done some searching around the internet and this site, but I haven't found a good way to count the context switches on a thread in a c++ program I am running. I need to know if it get swapped off of a CPU for correct timing.
View 4 Replies View RelatedProgramming :: Which Is Scheduling Algorithm Which Will Make Thread O?
May 4, 2011I have a timer thread, and when it expires, it sets a flag. The only problem is, if any higher priority thread comes in between, then the timer is not expired in real time.Thus i want to set a highest priority to my thread. Now, i know 2 algos, which can make my thread in real time are: SCHED_FIFO and SCHED_RR.
So, here are my queries: 1) Which scheduling algo is best suited for this purpose? 2) Is it guaranted to work in real time if i use that algo (you suggest in 1) and set the max_priority by getting the maximum settable priority for that particular algorithm using, int sched_get_priority_max(int policy);
Programming :: Change Priority When Creating New Thread?
Feb 21, 2010I have created an error logger thread in my application using pthread_create(), I want this thread to have a lower priority than my application's priority so that the application would run properly. Is there an easy way to do this? I know that we can change priority for thread created with policies FIFO or RR, since I don't set the policy for my application, I don't know what to set for my thread.
View 4 Replies View RelatedProgramming :: Suspend/resume A Thread When Using Pthread.h?
Dec 14, 2010I 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 RelatedProgramming :: Increasing Thread Stack Size?
Jan 23, 2011I seem to only be able to set my stack size on my linux server to 15000. If I increase it to 20000 I get a Segmentation Fault. how I can get the linux OS to increase the stack size? Code: threadRet |= pthread_attr_setstacksize( &m_ThreadAttributes, 15000 );
View 8 Replies View RelatedProgramming :: Need To Find Appropriate Thread Scheduling And Priority
Sep 9, 2009I am new to thread programming. I need to generate one thread in one process using posix thread. Which scheduling and priority do i need to use? I want to generate the thread with the lowest priority. As i know there are 3 scheduling policy available SCHED_FIFO, SCHED_RR or SCHED_OTHAR.
View 1 Replies View RelatedProgramming :: Passing An Object To A Running Thread?
Jan 14, 2011This is a client server issue where the server creates a new thread for listening to a new client, now when the thread starts execution and during its execution the server needs to pass it an object of some X class, how's that to be done?
View 4 Replies View RelatedProgramming :: Passing Array To Thread Function?
Aug 12, 2010I am trying to pass an array to thread program. Its printing the val[0] value but its not printing value at val[1]. Can somebody help me with this problem.
Code:
#include <unistd.h>
#include <stdlib.h>
[code]....
Programming :: Posting A Better Solution To A Closed Thread?
Jul 27, 2010Rather than get in hot (or even slightly-above-comfortable temperature) water for reviving a closed (ca. 2007) thread without moderator permission or acquaintance of the OP personally or by proxy, I'll post this alternate solution (approach?) along with one positive real-world example illustrating how mine is easier to write and is equally reliable, if not altogether better. The thread is here. Their solution:
Code:
if [ "$myfilesize" eq "0" ];then echo "$file: the file size is zero"; else echo "$file: the file size is NOT zero"; fi (and this hangs on the output of a stat -c %s command). "Hangs" is probably a most appropriate word. The two outputs, using two different stat options, the same file, and three marginally-different command-line syntaxes I just tried gave me these: First, using their approach, I got this:
Code:
tjsfa070929-094.jpg.error: the file size is NOT zero
Even though stat gave me this
Code:
>> stat -c %s $file
[Code]...
From where I sit, getting the file type string instead of an integer, which can be equally (if not often more) accurate, makes for an easier time of setting the conditional and, maybe only in terms of a few ticks, a faster script from start to finish. I think my method is better, and proven so to the limits of my knowledge and ability here in this OP.
Programming :: Create The Thread Which Runs Then Drops Out?
Mar 11, 2010I hope someone can help me with this. I need to call the same thread multiple times, but only run one thread at a time. So what I do is create the thread which runs then drops out. Run the main loop and after some time pthread_create the same thread again. So in pseudo code
[Code]...
I always presumed if I run a thread and it reaches with a pthread_exit, then the thread was destroyed? However I've found that after I've created the thread several 100 times the programme crashes? So can anyone advise how I call the same thread over and over?