Sponsored Content
Top Forums Programming pthread question : global variable not updated Post 302609957 by pflynn on Tuesday 20th of March 2012 03:59:46 PM
Old 03-20-2012
You can visualize what Corona688 said by "forcing" a context switch: if you put the main thread to sleep "for enough time" just after the new thread creation:

PHP Code:
int main()
{
   
pthread_t tid1tid2;
    
int t;
 
    
display();
    
pthread_create(&tid1,NULL,process,&t);
    
sleep(1); /* give some time so the new created thread will have a chance to run before main thread calls display function */
    
display();
   return 
0;
 
  } 
 

10 More Discussions You Might Find Interesting

1. AIX

pthread lock question

Is it possible that the function "pthread_cond_broadcast" block itself and the function "pthread_cond_wait" unblock in multi-threads programming ? The operating system is AIX 5.2, its maintenance level is : 5.2.0.4, VisualAge C++ 6.0. Thanks (0 Replies)
Discussion started by: Frank2004
0 Replies

2. AIX

pthread performance question

Running dedicated on AIX with 4 processors, creating 4 threads, each with equal work to do, only runs about 20% faster than 1 thread with all of the work. Test case has no blocking but does share memory for read access only. Any ideas why I'm only seeing 20% gain? Is this typical on AIX? ... (1 Reply)
Discussion started by: ldarden
1 Replies

3. Shell Programming and Scripting

Global variable

I have written a shell scritp in which i am using a variable which is declared before a while loop and i am updaitng the variable in while loop and want to use its updated value outside the loop. I am not able to do so, b'coz the scope of the variable is limited to the while loop only and when i am... (5 Replies)
Discussion started by: deepanshu
5 Replies

4. Programming

a question about pthread performance

Hello, I run my pthread code on Linux with 4 processors. However, the speed up is only 2 times. The code is about solving equation (G+s(i)C)z(i)=B*us(i), i=1,...,n. Here G,C are m*m matrix, B*us(i) is a m*1 vector and s(i) are n different numbers. I need to solve the equation n times to... (1 Reply)
Discussion started by: mgig
1 Replies

5. Shell Programming and Scripting

Help with Global Variable

Hi Guyz, I have a requirement like, i have to run a script every hour to count the number of errors encountered. At the end of the day, i need to send them the total number of errors, that have ocurred the entire day. For eg. if 10 errors occurred for starting 1 hr, 5 for next 1 hr, so on.... (1 Reply)
Discussion started by: DTechBuddy
1 Replies

6. Programming

pthread and mutex question

Hello, I have got some issue with the struct variable with passed arguments the variable in the sturct is only recognize the last value their assigned to I'm pretty confused why the mutex didn't work out here is my program: #include<stdio.h> #include<pthread.h> pthread_mutex_t lock... (3 Replies)
Discussion started by: michael23
3 Replies

7. Shell Programming and Scripting

Global variable value

Hi All, Im new to shell scripting. I am running EgA.sh and setting one global variable XYZ=0 . Also calling another EgB.sh from EgA.sh, changing the value of XYZ=10 but after executing EgB.sh, value of XYZ is still 0. Im expecting it to be 10. Anyone for help. Thanks in Advance. :) (5 Replies)
Discussion started by: paliwal
5 Replies

8. Shell Programming and Scripting

Global Variable

Hi, I have created a variable say today at the begin having 123 as its value and inside a for loop it gets resolved to some value say 150 in its first iteration. How can I use this value 150 ( 1st iteration's ) outside the scope of for loop ?. In the same way I wanted to use all iteration's... (1 Reply)
Discussion started by: penqueen
1 Replies

9. Shell Programming and Scripting

Question around Global Variable

Hi, I am using Linux and sh shell count=7 find * -prune -type d | sort -r -n | ( while read d; do if ; then echo "FOUND COUNTER1 is: $count" break 2; fi done echo "FOUND COUNTER2 is: $count" ) if ; then echo "Problem: Multiple or NO records...Please CHECK !!" fi Output: ... (4 Replies)
Discussion started by: mohtashims
4 Replies

10. Shell Programming and Scripting

[bash] why my variable is not updated?

Does anyone know why the below script is not working? Why is not the variable tot_files updated? location=$1 cd "$location" tot_files=0 ( echo "" # recursively gets the total number of files tot_files=$(for t in files ; do echo `find . -type ${t:0:1} | wc -l` $t | cut -f1... (12 Replies)
Discussion started by: soichiro
12 Replies
PTHREAD_CREATE(3)					   BSD Library Functions Manual 					 PTHREAD_CREATE(3)

NAME
pthread_create -- create a new thread LIBRARY
POSIX Threads Library (libpthread, -lpthread) SYNOPSIS
#include <pthread.h> int pthread_create(pthread_t *thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg); DESCRIPTION
The pthread_create() function is used to create a new thread, with attributes specified by attr, within a process. If attr is NULL, the default attributes are used. If the attributes specified by attr are modified later, the thread's attributes are not affected. Upon suc- cessful completion pthread_create() will store the ID of the created thread in the location specified by thread. The thread is created executing start_routine with arg as its sole argument. If the start_routine returns, the effect is as if there was an implicit call to pthread_exit() using the return value of start_routine as the exit status. Note that the thread in which main() was origi- nally invoked differs from this. When it returns from main(), the effect is as if there was an implicit call to exit() using the return value of main() as the exit status. The signal state of the new thread is initialized as: o The signal mask is inherited from the creating thread. o The set of signals pending for the new thread is empty. RETURN VALUES
If successful, the pthread_create() function will return zero. Otherwise an error number will be returned to indicate the error. ERRORS
The pthread_create() function will fail if: [EAGAIN] The system lacked the necessary resources to create another thread, or the system-imposed limit on the total number of threads in a process [PTHREAD_THREADS_MAX] would be exceeded. [EPERM] The caller does not have appropriate permission to set the required scheduling parameters or scheduling policy. [EINVAL] The value specified by attr is invalid. SEE ALSO
fork(2), pthread_attr(3), pthread_cancel(3), pthread_cleanup_pop(3), pthread_cleanup_push(3), pthread_exit(3), pthread_join(3) STANDARDS
The pthread_create() function conforms to ISO/IEC 9945-1:1996 (``POSIX.1''). BSD
March 15, 2014 BSD
All times are GMT -4. The time now is 03:54 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy