The following restrictions apply: 1) One thread will print \"hello \", one threa
ID: 3591686 • Letter: T
Question
The following restrictions apply:
1) One thread will print "hello ", one thread will print "world", and the main function will print the trailing " ",
2) Ensure thread synchronization using pthread mutex
/* Include Files */
#include <stdio.h>
/* External References */
extern void world( void );
extern void hello( void );
void main( int argc, char *argv[] ) {
world();
hello();
printf( " " );
}
/* world - print the "world" part. */
void world( void ) {
printf( "world" );
}
/* hello - print the "hello" part. */
void hello( void ) {
printf( "hello " );
}
Explanation / Answer
#include<stdio.h>
#include<string.h>
#include<pthread.h>
#include<stdlib.h>
#include<unistd.h>
pthread_t tid[2];
int counter;
pthread_mutex_t lock;
void* doSomeThing(void *arg)
{
pthread_mutex_lock(&lock);
unsigned long i = 0;
counter += 1;
printf(" Job %d started ", counter);
for(i=0; i<(0xFFFFFFFF);i++);
printf(" Job %d finished ", counter);
pthread_mutex_unlock(&lock);
return NULL;
}
int main(void)
{
int i = 0;
int err;
if (pthread_mutex_init(&lock, NULL) != 0)
{
printf(" mutex init failed ");
return 1;
}
while(i < 2)
{
err = pthread_create(&(tid[i]), NULL, &doSomeThing, NULL);
if (err != 0)
printf(" can't create thread :[%s]", strerror(err));
i++;
}
pthread_join(tid[0], NULL);
pthread_join(tid[1], NULL);
pthread_mutex_destroy(&lock);
return 0;
}