Creating and Managing Threads
Use POSIX threads (pthread) to create and control threads in C.
Creating and Managing Threads is a free C Academy lesson on CoddyKit — lesson 2 of 3. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the C Academy learning path, one of 3 lessons in the course, and your progress syncs across the web and the CoddyKit app.
1
Creating and Managing Threads
In multithreading, we create multiple threads to execute tasks concurrently.
In this lesson, you will learn:
- How to create multiple threads in C.
- How to wait for threads to finish execution.
- How to pass arguments to threads.
2
Creating Multiple Threads
We use pthread_create() to create multiple threads.
Syntax:
pthread_create(&thread, NULL, function, argument);
Each thread runs independently but shares memory with other threads.
3
Example: Creating Multiple Threads
This program creates multiple threads that run concurrently.
#include <stdio.h>
#include <pthread.h>
void *printMessage(void *arg) {
printf("Thread %d: Hello from thread!\n", *(int*)arg);
return NULL;
}
int main() {
pthread_t threads[3];
int thread_ids[3] = {1, 2, 3};
for (int i = 0; i < 3; i++) {
pthread_create(&threads[i], NULL, printMessage, &thread_ids[i]);
}
for (int i = 0; i < 3; i++) {
pthread_join(threads[i], NULL);
}
return 0;
}4
Waiting for Threads to Finish
Use pthread_join() to wait for a thread to complete.
Syntax:
pthread_join(thread, NULL);
Without pthread_join(), the main thread may exit before other threads finish.
5
Passing Arguments to Threads
Arguments can be passed to a thread function using a pointer.
Example:
pthread_create(&thread, NULL, function, (void*)&value);
The thread function casts the argument back to its original type.
6
Example: Passing Arguments to Threads
This program demonstrates how to pass arguments to a thread function.
#include <stdio.h>
#include <pthread.h>
void *printNumber(void *arg) {
int num = *(int*)arg;
printf("Thread received number: %d\n", num);
return NULL;
}
int main() {
pthread_t thread;
int value = 10;
pthread_create(&thread, NULL, printNumber, &value);
pthread_join(thread, NULL);
return 0;
}7
Terminating a Thread
Use pthread_exit() to terminate a thread explicitly.
Example:
pthread_exit(NULL);
The main function should also call pthread_exit() if needed.
8
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Best Practices for Managing Threads
To manage threads efficiently:
- Always use
pthread_join()to avoid premature termination. - Pass arguments using pointers to avoid data corruption.
- Minimize shared resource conflicts.
10
Summary
In this lesson, you learned:
- How to create multiple threads using
pthread_create(). - How to wait for threads using
pthread_join(). - How to pass arguments to threads.
- How to terminate a thread safely.
Next, we will explore synchronization and race conditions in multithreading!
Frequently asked questions
Is the “Creating and Managing Threads” lesson free?
Yes — the full text of “Creating and Managing Threads” is free to read here on the web, and the C Academy course includes 3 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the C Academy course, upgrade to CoddyKit PRO.
What will I learn in “Creating and Managing Threads”?
Use POSIX threads (pthread) to create and control threads in C. You practise C Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start C Academy?
No prior experience is required. C Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 2 of 3, so you can start here or from the beginning and move at your own pace.
How long does the “Creating and Managing Threads” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this C Academy lesson?
Yes. Every C Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Introduction to Threads
- Creating and Managing Threads
- Synchronization and Race Conditions