#include <stdio.h>#include "mbuff.h"/* the contents of shared memory may change at any time, thus volatile */volatile char * shm1, *shm2;main (int argc,char *argv[]){   	shm1 = (volatile char*) mbuff_alloc("demo1",1024*1024);	shm2 = (volatile char*) mbuff_alloc("demo1",1024*1024);	if( shm1 == NULL || shm2 == NULL ) {		printf("mbuff_alloc failed\n");		exit(2);	}	sprintf((char*)shm1,"example data\n");	sleep(5); /* you may change it from the kernel or other program here */	printf("shm1=%p shm2=%p shm2->%s", shm1, shm2, shm2);	mbuff_free("demo1",(void*)shm1);	sleep(3);	/* you may still access shm2 here, it is still the same memory area */	mbuff_free("demo1",(void*)shm2);	return(0);}