We know that Linux or Unix systems are multi-user and multi-tasking environments. Hence the processes in these environments can cooperate with each other. In a multi-threaded system, generally, threads share a segment of memory instead of allocating memory for each thread separately.
Source code of Multi-Threaded Program
#include <pthread.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#define NO_OF_THREADS 3
void *my_thread_function(void *arg);
char msg[] = "My Multi-Thread Program";
int main(void)
{
int i, length;
char *str;
pthread_t mythreads[NO_OF_THREADS];
void *thread_result;
for(i = 0; i < NO_OF_THREADS; i++)
{
length = snprintf( NULL, 0, "%d", i);
str = malloc( length + 1 );
snprintf( str, length + 1, "%d", i);
if (pthread_create(&mythreads[i], NULL, my_thread_function, (void *)str))
{
printf("\nError in creating a thread!");
exit(EXIT_FAILURE);
}
}
printf("\nWaiting for the thraed to finish....");
for(i = 0; i < NO_OF_THREADS; i++)
{
if (pthread_join(mythreads[i], &thread_result))
{
printf("Error in joining this thread!");
exit(EXIT_FAILURE);
}
printf("\nThread joined successfully and it returned %s\n", (char *)thread_result);
}
exit(EXIT_SUCCESS);
printf("\nAll the threads completed!");
}
void *my_thread_function(void *arg) {
int i;
printf("my_thread_function has been started. Argument is %s\n", (int *)arg);
for (i = 0; i < 5; i++)
{
printf("I am in a thread %s !\n", (char *)arg);
sleep(1);
strcpy(msg, "Bye!");
}
pthread_exit("my_thread_function is being completed.");
}
Compile it as
$ gcc mythreadtest.c -o mythreadtest -lpthread
Run it as
$ ./mythreadtest
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