offset = lseek(z_fd, offset, SEEK_SET);
if ((qty = read(z_fd, header, Z_FILE_HEADER_BYTES))< Z_FILE_HEADER_BYTES)
fprintf(stderr, "Warning: Tried to read %ld header bytes but only got %ld. Will do my best\n", Z_FILE_HEADER_BYTES, qty);
offset = lseek(z_fd, offset, SEEK_SET);
if ((qty = read(z_fd, header, Z_FILE_HEADER_BYTES))< Z_FILE_HEADER_BYTES)
fprintf(stderr, "Warning: Tried to read %ld header bytes but only got %ld. Will do my best\n", Z_FILE_HEADER_BYTES, qty);