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//example 2: create 2 threads

#include <pthread.h>

#include <stdio.h>

//parameters to print function

struct char_print_parms

{

            char character; //character to print

            int count; // times to print

};

//Ham xu ly cua thread

//In ky tu ra man hinh, duoc cho boi tham so la mot con tro den cau truc du lieu tren

void* char_print(void* params)

{

            struct char_print_parms* p = (struct char_print_parms*) params; //ep kieu tham so truyen vao

            int i;

            int n = p->count; //Bien chua so lan in ra

            char c=p->character; //Bien chua ma ky tu muon in ra

            for(i=0;i<n;i++)

                        fputc(c,stdout); //Ham in 1 ky tu ra thiet ra chuan

            return NULL;

}

int main(int argc, char** agrv)

{

            pthread_t  thread1_id, thread2_id; //2 bien doi tuong thread

            struct char_print_parms  p1, p2; //2 bien tham so truyen cho ham xu ly cua thread

            //Tao 1 thread in 30000 chu 'x'

            p1.character = 'x';

            p1.count = 30000;

            pthread_create(&thread1_id, NULL, &char_print, &p1);

            //Tao 1 thread khac in ra 20000 chu 'o'

            p2.character = 'o';

            p2.count = 20000;

            pthread_create(&thread2_id, NULL, &char_print, &p2);

            //Dam bao thread1 da ket thuc

            pthread_join(thread1_id, NULL);

            //Dam bao thread2 da ket thuc

            pthread_join(thread2_id, NULL);

            // Now we can safely return.

            return 0;

}

/*    Example 3. Programming threads. ARM LINUX COURSE                     */

/**********************************************************

* Chuong trinh:

* main: Thuc hien dieu khien led chay duoi

* thread: Thuc hien doc trang thai (polling) nut bam de thay doi toc do led

***********************************************************/

#include <pthread.h>

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <sys/ioctl.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <sys/select.h>

#include <sys/time.h>

#include <errno.h>

#define ON  1

#define OFF 0

/* Bien luu thoi gian delay */

// Thay doi khi K1, K2 duoc an 

static int t = 1000; //don vi la milisecond, ban dau mac dinh la 1000 ms

pthread_mutex_t mutex1 = PTHREAD_MUTEX_INITIALIZER;

/* Ham sleep ms su dung usleep cua linux */ 

void sleepms(int ms)

{

//usleep in us, sleep in second

usleep(1000*ms); //convert to microseconds

return;

};

/* Cau truc du lieu se truyen tham so cho thread */

struct thread_parms

{

char btn[6];

int btn_fd;

};

/* Ham xu ly cua thread thuc hien doc nut K1, K2 (polling) */

void* btn_polling(void* param);

int main(int argc, char** agrv)

{

int led_fd, button_fd; //# of device file 

struct thread_parms p; //Bien cau truc chua tham so se truyen cho ham xu ly cua thread

pthread_t thread_id;   //# of thread

int led_no; //So hieu led 0-4

//Mang chua gia tri trang thai 6 button se doc

char buttons[6] = {'0', '0', '0', '0', '0', '0'}; 

int i; 

//Mo thiet bi (led port), can kiem tra chinh xac ten trong /dev

led_fd = open("/dev/leds", 0);

if (led_fd < 0) {

perror("open device leds");

exit(1);

}

else printf("open device led ok\n");

//Mo thiet bi (button port)

button_fd = open("/dev/buttons", 0); //mo button port

if(button_fd < 0) 

{

perror("open device buttons");

exit(1);

}

else printf("open device button ok\n");

//Chuan bi tham so truyen vao cho ham xu ly cua thread

p.btn_fd = button_fd; // button device file number

//memset(p.btn, '0', sizeof(p.btn)); //khoi tao buffer 

for(i=0;i<6;i++) p.btn[i]='0'; //buffer to read button status (K1-K6)

//Tao thread thuc hien polling button

thread_id = pthread_create(&thread_id, NULL, &btn_polling, &p);

//Chuong trinh chinh (master thread) thuc hien hieu ung led duoi

//voi thoi gian delay chua trong bien t

//Ban dau tat ca cac led deu off

for(i=0;i<4;i++) ioctl(led_fd, OFF, i);

led_no=0;

while(1)

{

//Bat led led_no

ioctl(led_fd, ON, led_no);

//Sleep in t ms

sleepms(t); 

//Tat led led_no va chuan bi bat luon led ke tiep

ioctl(led_fd, OFF, led_no);

led_no++;

if(led_no == 4) led_no = 0;

}

close(button_fd);

close(led_fd);

return 0;

}

void* btn_polling(void* param)

{

struct thread_parms* p = (struct thread_parms*)param;

char cur_btn[6], old_btn[6];

int btn_fd;

int i;

for(i=0;i<6;i++) old_btn[i] = p->btn[i];

btn_fd = p->btn_fd; 

for(;;)//Lien tuc tham do trang thai nut bam (K1, K2 co duoc an)

{

int num=read(btn_fd, cur_btn, sizeof(cur_btn));

if(num != sizeof(cur_btn))

{

perror("read buttons:");

exit(1);

}

//Chi can doc K1, K2 tuong ung voi tang/giam led speed

//Doc K1

if(old_btn[0] != cur_btn[0])

{

old_btn[0] = cur_btn[0];

printf("K1 is pressed/released\n");

//Can dung mutex cho bien t ?

pthread_mutex_lock( &mutex1 );

t = t+50; //tang thoi gian delay

pthread_mutex_unlock( &mutex1 );

}

//Doc K2

if(old_btn[1] != cur_btn[1])

{

old_btn[1] = cur_btn[1];

printf("K2 is pressed/released\n");

//Can dung mutex cho bien t ?

pthread_mutex_lock( &mutex1 );

t = t-50; //giam thoi gian delay

if(t < 100) t = 100;

pthread_mutex_unlock( &mutex1 );

}

}

return NULL;