GJ_HEADER_MAGIC
bcopy(GJ_HEADER_MAGIC, data, sizeof(GJ_HEADER_MAGIC));
data += sizeof(GJ_HEADER_MAGIC);
if (bcmp(hdr->jh_magic, GJ_HEADER_MAGIC, sizeof(GJ_HEADER_MAGIC)) != 0)
strlcpy(hdr.jh_magic, GJ_HEADER_MAGIC, sizeof(hdr.jh_magic));
char jh_magic[sizeof(GJ_HEADER_MAGIC)];