Creating Threads In C
Creating and passing data to threads.
Use pthread_create
to create threads and pass data using a struct
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#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <assert.h>
#define NUM_THREADS 8
typedef struct {
int thread_num;
char *message;
int len;
} thread_arg_t;
void *thread_main(void *p_arg) {
thread_arg_t *p = p_arg;
sleep(1 + 5*((*p).thread_num % 2));
(*p).len = strlen((*p).message);
printf("Thread #%d: %s length=%d\n", (*p).thread_num, (*p).message, (*p).len);
return NULL;
}
int main(int argc, char *argv[]) {
pthread_t tid[NUM_THREADS];
thread_arg_t args[NUM_THREADS];
char *messages[NUM_THREADS];
int status = 0;
messages[0] = "English: Hello World!";
messages[1] = "French: Bonjour, le monde!";
messages[2] = "Spanish: Hola al mundo";
messages[3] = "Klingon: Nuq neH!";
messages[4] = "German: Guten Tag, Welt!";
messages[5] = "Russian: Zdravstvuyte, mir!";
messages[6] = "Japan: Sekai e konnichiwa!";
messages[7] = "Latin: Orbis, te saluto!";
int i ;
for (i = 0; i < NUM_THREADS; i++) {
args[i].thread_num = i;
args[i].message = messages[i];
printf("Creating thread #%d\n", i);
status = pthread_create(&tid[i], NULL, thread_main, &args[i]);
assert(status == 0);
}
for (i = 0; i < NUM_THREADS; i++) {
status = pthread_join(tid[i], NULL);
assert(status == 0);
}
pthread_exit(NULL);
}
Written on November 30, 2018