156 	struct tm t, gm;  in cd9660_compute_gm_offset()  local
159 	(void)gmtime_r(&tim, &gm);  in cd9660_compute_gm_offset()
160 	gm.tm_year -= t.tm_year;  in cd9660_compute_gm_offset()
161 	gm.tm_yday -= t.tm_yday;  in cd9660_compute_gm_offset()
162 	gm.tm_hour -= t.tm_hour;  in cd9660_compute_gm_offset()
163 	gm.tm_min  -= t.tm_min;  in cd9660_compute_gm_offset()
164 	if (gm.tm_year < 0)  in cd9660_compute_gm_offset()
165 		gm.tm_yday = -1;  in cd9660_compute_gm_offset()
166 	else if (gm.tm_year > 0)  in cd9660_compute_gm_offset()
167 		gm.tm_yday = 1;  in cd9660_compute_gm_offset()
169 	return (char)(-(gm.tm_min + 60* (24 * gm.tm_yday + gm.tm_hour)) / 15);  in cd9660_compute_gm_offset()