I’m using std::thread to launch threads. Also, I need stats for the worker thread available at /proc/[pid]/tasks/[tid]. I need tid to be able to monitor thread stats. I was wondering if there was a way to extract tid from the parent thread. I know that syscall gettid() from the worker returns its id, bu…
Tag: pthreads
How to fix occasional EINVAL error when calling pthread_create
The Problem When I create a detached thread using the code below, pthread_create will sometimes return EINVAL. I would like to know why this is happening and what I should do to fix it. When the error occurs, the code below will print the following line: Error creating thread. errno = 22: Invalid argument Wha…
Thread Program on Linux (Posix Thread)
I want to modify the multithread program on the Linux operating system using this Pthread API. I want to change that program into a program that has 2 threads that work together to add a number. But i don’t know how to change it, Thanks again for any help that can be offered. I am sorry,because I’…
How does pthread_cond_wait (conditon variable) unblock all threads only once, not multiple times?
I have successfully implemented a producer thread and 2 worker threads or consumer threads. The producer thread broadcasts condition using pthread_cond_broadcast. And the worker threads are blocked by pthread_cond_wait. The code looks something likes this: Thread 1 (Producer Thread): Thread 2 (Worker/Consumer…
How can I accomplish multiple threads to join multiple times into a process? (pthread_mutex_lock)
I want to write a program, what counts to 100. I want to accomplish this with 10 threads, using pthread lock. When the program steps into a thread it generates a number between 0-2, this value will be added to it’s index of array and also to the global variable sum. When the sum value reaches 100, every…
Centos 7 with PHP 7.2 Pthreads unable to load redis.so
I recently setup a new Centos 7 system with php 7.2 and Redis. This is working fine. This was my yum install of the php packages. yum install php72.x86_64 php72-php-cli.x86_64 php72-php-common.x86_64 php72-php-devel.x86_64 php72-php-fpm.x86_64 php72-php-gd.x86_64 php72-php-json.x86_64 php72-php-mbstring.x86_6…
How to write integers from file to buffer using POSIX pthreads in Linux?
I want to write a program to get integers from a file and put them in a buffer using multiple threads. The buffer size is 20 and there are 100 integers. I can’t use for-loop because one thread should read one integer at a time. As an example, if we are using one thread that thread must run 100 times
Multithreading with Semaphor, Mutex and PThread
Me and a friend are currently working on basic multithreading examples for university in c. We’re supposed to solve the producer/consumer problem with a multithreaded buffer. We’ve got a working version using mutex and conditional variables, but trying to solve this using semaphores and mutex were…
Segmentation Fault on pthread_create
I am having an issue with the following C code. The code itself is supposed to create 5 threads that simulate the Dining Philosophers problem in which threads are accessing shared data. The code follows: I am on a Linux virtual machine, using gedit. The program compiles fine, but upon attempting to run it, I …
PHP Thread compilation not working
I am attempting to use pthreads with Apache FPM. Step 1. After installing and recompiling php according to: https://blog.programster.org/ubuntu16-04-compile-php-7-2-with-pthreads The server works as expected and I can run pthreads from CLI. Step 2. Then I need to run threads from a web server so I followed th…