#include <sys/types.h>#include <sys/stat.h>#include <unistd.h>#include <stdio.h>#include <signal.h>#include <syslog.h>#define SLEEP_TIME 5//get the mail sizelong get_file_size(const char* filename) {	struct stat status; 	long size;	if(stat(filename,&status)==-1){	       perror("cannot get the file status");	       return -1;	} 		size=status.st_size;	return size; } void mail_log(const char* progname,const char* mail_pos){	fprintf(stderr,"%s notice: You hava new mail in %s\n",progname,mail_pos);}int check_mail(const char *filename,const char* progname) { 	long old_mail_size;	long mail_size; 	old_mail_size=get_file_size(filename); 	if(old_mail_size==-1)		return 1; 	if(old_mail_size>0) 		mail_log(progname,filename); 	sleep(SLEEP_TIME); 	while(1){ 		mail_size=get_file_size(filename); 				if(mail_size!=old_mail_size){			mail_log(progname,filename); 		}		old_mail_size=mail_size; 				sleep(SLEEP_TIME); 	} }