NAME
types - primitive system data types

SYNOPSIS
#include <sys/types.h>

DESCRIPTION
The data types defined in the include file are used in UNIX system
code; some data of these types are accessible to user code:

/*
* Basic system types and major/minor device constructing/busting macros.
*/

/* major part of a device */
#define major(x) ((int)(((unsigned)(x)>>8)&0377))

/* minor part of a device */
#define minor(x) ((int)((x)&0377))

/* make a device number */
#define makedev(x,y) ((dev_t)(((x)<<8) | (y)))

typedef unsigned char u_char;
typedef unsigned short u_short;
typedef unsigned int u_int;
typedef unsigned long u_long;
typedef unsigned short ushort;/* sys III compat */

#ifdef vax
typedef struct _physadr { int r[1]; } *physadr;
typedef struct label_t {
int val[14];
} label_t;
#endif
#ifdef ibmrt
typedef struct _physadr { int r[1]; } *physadr;
typedef struct label_t {
int val[16];
} label_t;
#endif
#ifdef mc68000
typedef struct _physadr { short r[1]; } *physadr;
typedef struct label_t {
int val[13];
} label_t;
#endif
typedef struct _quad { long val[2]; } quad;
typedef long daddr_t;
typedef char * caddr_t;
typedef u_long ino_t;
typedef long swblk_t;
typedef long size_t;
typedef long time_t;
typedef short dev_t;
typedef long off_t;
typedef u_short uid_t;
typedef u_short gid_t;

#define NBBY 8 /* number of bits in a byte */
/*
* Select uses bit masks of file descriptors in longs.
* These macros manipulate such bit fields (the filesystem macros use
* chars). FD_SETSIZE may be defined by the user, but the default here
* should be >= NOFILE (param.h).
*/
#ifndef FD_SETSIZE
#define FD_SETSIZE 256
#endif

typedef long fd_mask;
#define NFDBITS (sizeof(fd_mask) * NBBY)/* bits per mask */
#ifndef howmany
#define howmany(x, y) (((x)+((y)-1))/(y))
#endif

typedef struct fd_set {
fd_mask fds_bits[howmany(FD_SETSIZE, NFDBITS)];
} fd_set;

#define FD_SET(n, p) ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n)
% NFDBITS)))
#define FD_CLR(n, p) ((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n)
% NFDBITS)))
#define FD_ISSET(n, p) ((p)->fds_bits[(n)/NFDBITS] & (1 << ((n)
% NFDBITS)))
#define FD_ZERO(p) bzero((char *)(p), sizeof(*(p)))

The form daddr_t is used for disk addresses except in an i-node on
disk. Times are encoded in seconds since 00:00:00 GMT, January 1,
1970. The major and minor parts of a device code specify kind and
unit number of a device and are installation-dependent. Offsets
are measured in bytes from the beginning of a file. The label_t
variables are used to save the processor state while another
process is running.