singleton_multithread.c

#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>

#define INIT_VALUE 1.0f
pthread_mutex_t m;

float *getValue(){

	static int is_initialized = 0;
	static float *actual_data = NULL;

	if(!is_initialized){
		pthread_mutex_lock(&m);
			if(!is_initialized){
				actual_data = (float *)malloc(sizeof(float));
				*actual_data = INIT_VALUE;
				is_initialized = 1;
			}		
			printf("*********** intialised ***************\n");
		pthread_mutex_unlock(&m);
	}
	return actual_data;
}

void *func1(void *t){
	printf("%p\n",getValue());
	return NULL;
}

int main(){
	if(pthread_mutex_init(&m,NULL))
		printf("%s\n", "error init mutex");
	
	int i=0;
	pthread_t t1[100];

	for(i=0;i<100;++i){
		if(pthread_create(&t1[i], NULL, func1,NULL))
			printf("%s\n", "error creating thread");
	}



	for(i=0;i<100;++i){
		if(pthread_join(t1[i],NULL))
			printf("%s\n", "error creating thread");
	}
	// pthread_t t2;


	
		
	// pthread_create(&t2, NULL, func1,NULL);



	// pthread_join(t2,NULL);
	
	float *temp = getValue();	
	free(temp);
	return 0;
}

Problem is in line 10