g_sectorsize
size = g_sectorsize(fd);
offset = g_mediasize(fd) - g_sectorsize(fd);
secsize = g_sectorsize(provfd);
if (g_sectorsize(fd) == -1) {
ssize_t g_sectorsize(int);
secsize = g_sectorsize(f);
secsize = g_sectorsize(f);
u = g_sectorsize(fd);
sectorsize = g_sectorsize(fd);
sectorsize = g_sectorsize(fd);
sectorsize = g_sectorsize(fd);
sectorsize = g_sectorsize(fd);
disk.sectorsize = g_sectorsize(disk.fd);