Threading in C

Question

I want to create a thread in C so that the thread automatically call after two seconds. I am using Visual Studio and Windows platform for development.

How do I get started?

Answer 1

You are going to need to use OS specific libraries to do threading. On Posix, you will want to look into pthreads (and specifically pthread_create). On Windows, you'll want CreateThread or _beginthreadex.

Answer 2

Multithreading in C is platform dependent. You need to use external libraries corresponding to different platforms.

Read about:

Multithreading in C, POSIX style and Multithreading with C and Win32

Answer 3

There's nothing in standard C that could help you. You need to use some library or platform-dependent features. Don't forget that many platforms simply don't have threads - only full-weight processes.

On Windows use CreateThread(). You'll need Microsoft SDK to compile your code using this and other Win32 functions.

Answer 4

C doesn't have built in threading facilities; you will have to use your OS services to create a thread.

For windows use CreateThread function.

Answer 5

You can check this link for different ways to do it: Windows threading: _beginthread vs _beginthreadex vs CreateThread C++

For cross-platform code, you can also check the Boost library or Intel Threading Building Blocks.

Answer 6

Please refer to MSDN for VC8. Refer to the createThread() help there. That should give you sufficient information.

For checking online, please go the link below:

http://msdn.microsoft.com/en-us/library/ms682453(VS.85).aspx

Answer 7

Here is a sample program for Single Threading and Multithreading in Win32API written in C will work on Visual studio.

SingleThread.c

#include<stdio.h>
#include<stdlib.h>
#include<Windows.h>

DWORD WINAPI funHello(void *x)
{
    int c = (int*)x;
    printf("\n Thread No: %d\n",c);
    Sleep(2000);
    return 0;
}

int main()
{
    HANDLE  myhandle;
    DWORD threadId;
    int c = 1;
    myhandle = CreateThread(NULL, 0, funHello, (void *)c, 0, &threadId);
    if (myhandle == NULL)
    {
        printf("Create Thread Failed. Error no: %d\n", GetLastError);
    }
    WaitForSingleObject(myhandle, INFINITE);
    printf("\n Main Hello...\n");
    CloseHandle(myhandle);
    return 0;
}

MultiThreading.c

#include<stdio.h>
#include<stdlib.h>
#include<Windows.h>
#define NUM_THREADS 2     //  Define Number of threads here or take as user Input, 
                          // In yourquestion it is 2

DWORD WINAPI funHello(void *x)
{
    int c = (int*)x;
    printf("\n Thread No: %d\n",c);
    Sleep(2000);
    return 0;
}
int main()
{
    HANDLE *arrayThread;
    arrayThread = (int*)malloc(NUM_THREADS * sizeof(int));
    DWORD ThreadId;

    for (int i = 0; i < NUM_THREADS; i++)
    {
        arrayThread[i] = CreateThread(NULL, 0, funHello, (void *)i, 0, &ThreadId);
        if (arrayThread[i] == NULL)
        {
            printf("Create Thread %d get failed. Error no: %d", i, GetLastError);
        }
    }

    WaitForMultipleObjects(NUM_THREADS, arrayThread,TRUE,INFINITE);
    DWORD lpExitCode;
    BOOL result;

    for (int i = 0; i < NUM_THREADS; i++)
    {
        CloseHandle(arrayThread[i]);
    }
    printf("\n Hello Main..");
    return 0;
}