Работа потоков

#include <pthread.h>
#include <sys/types.h>
#include <stdio.h>
struct char_print_params
    { char character;
    int count;};
void *char_print(void *params)
{
struct char_print_params *p=(struct char_print_params*)params;
int i;
for(i=0;i<p->count;i++)
    fputc(p->character,stderr);
return NULL;
}
int main()
{
pthread_t thread1_id,thread2_id;
struct char_print_params thread1_args,thread2_args;
thread1_args.character='x';
thread1_args.count=100;
pthread_create(&thread1_id,NULL,&char_print,&thread1_args);
thread2_args.character='y';
thread2_args.count=150;
pthread_create(&thread2_id,NULL,&char_print,&thread2_args);
pthread_join(thread1_id,NULL);
pthread_join(thread2_id,NULL);
return 0;
}

struct char_print_params
    { char character;
    int count;};
void *char_print(void *params)
{
struct char_print_params *p=(struct char_print_params*)params;
int i;
for(i=0;i<p->count;i++)
    fputc(p->character,stderr);
return NULL;
}