FreeBSD/Linux Kernel Cross Reference
sys/include/sys/types.h

     /* The <sys/types.h> header contains important data type definitions.
      * It is considered good programming practice to use these definitions, 
      * instead of the underlying base type.  By convention, all type names end 
      * with _t.
      */
     
     #ifndef _TYPES_H
     #define _TYPES_H
     
    #ifndef _ANSI_H
    #include <ansi.h>
    #endif
    
    /* The type size_t holds all results of the sizeof operator.  At first glance,
     * it seems obvious that it should be an unsigned int, but this is not always 
     * the case. For example, MINIX-ST (68000) has 32-bit pointers and 16-bit
     * integers. When one asks for the size of a 70K struct or array, the result 
     * requires 17 bits to express, so size_t must be a long type.  The type 
     * ssize_t is the signed version of size_t.
     */
    #ifndef _SIZE_T
    #define _SIZE_T
    typedef unsigned int size_t;
    #endif
    
    #ifndef _SSIZE_T
    #define _SSIZE_T
    typedef int ssize_t;
    #endif
    
    #ifndef _TIME_T
    #define _TIME_T
    typedef long time_t;               /* time in sec since 1 Jan 1970 0000 GMT */
    #endif
    
    #ifndef _CLOCK_T
    #define _CLOCK_T
    typedef long clock_t;              /* unit for system accounting */
    #endif
    
    #ifndef _SIGSET_T
    #define _SIGSET_T
    typedef unsigned long sigset_t;
    #endif
    
    /* Open Group Base Specifications Issue 6 (not complete) */
    typedef long useconds_t;        /* Time in microseconds */
    
    /* Types used in disk, inode, etc. data structures. */
    typedef short          dev_t;      /* holds (major|minor) device pair */
    typedef char           gid_t;      /* group id */
    typedef unsigned long  ino_t;      /* i-node number (V3 filesystem) */
    typedef unsigned short mode_t;     /* file type and permissions bits */
    typedef short        nlink_t;      /* number of links to a file */
    typedef unsigned long  off_t;      /* offset within a file */
    typedef int            pid_t;      /* process id (must be signed) */
    typedef short          uid_t;      /* user id */
    typedef unsigned long zone_t;      /* zone number */
    typedef unsigned long block_t;     /* block number */
    typedef unsigned long  bit_t;      /* bit number in a bit map */
    typedef unsigned short zone1_t;    /* zone number for V1 file systems */
    typedef unsigned short bitchunk_t; /* collection of bits in a bitmap */
    
    typedef unsigned char   u8_t;      /* 8 bit type */
    typedef unsigned short u16_t;      /* 16 bit type */
    typedef unsigned long  u32_t;      /* 32 bit type */
    
    typedef char            i8_t;      /* 8 bit signed type */
    typedef short          i16_t;      /* 16 bit signed type */
    typedef long           i32_t;      /* 32 bit signed type */
    
    typedef struct { u32_t _[2]; } u64_t;
    
    /* The following types are needed because MINIX uses K&R style function
     * definitions (for maximum portability).  When a short, such as dev_t, is
     * passed to a function with a K&R definition, the compiler automatically
     * promotes it to an int.  The prototype must contain an int as the parameter,
     * not a short, because an int is what an old-style function definition
     * expects.  Thus using dev_t in a prototype would be incorrect.  It would be
     * sufficient to just use int instead of dev_t in the prototypes, but Dev_t
     * is clearer.
     */
    typedef int            Dev_t;
    typedef int       _mnx_Gid_t;
    typedef int          Nlink_t;
    typedef int       _mnx_Uid_t;
    typedef int             U8_t;
    typedef unsigned long  U32_t;
    typedef int             I8_t;
    typedef int            I16_t;
    typedef long           I32_t;
    
    /* ANSI C makes writing down the promotion of unsigned types very messy.  When
     * sizeof(short) == sizeof(int), there is no promotion, so the type stays
     * unsigned.  When the compiler is not ANSI, there is usually no loss of
     * unsignedness, and there are usually no prototypes so the promoted type
     * doesn't matter.  The use of types like Ino_t is an attempt to use ints
     * (which are not promoted) while providing information to the reader.
     */
   
   typedef unsigned long  Ino_t;
   
   #if _EM_WSIZE == 2
   /*typedef unsigned int      Ino_t; Ino_t is now 32 bits */
   typedef unsigned int    Zone1_t;
   typedef unsigned int Bitchunk_t;
   typedef unsigned int      U16_t;
   typedef unsigned int  _mnx_Mode_t;
   
   #else /* _EM_WSIZE == 4, or _EM_WSIZE undefined */
   /*typedef int             Ino_t; Ino_t is now 32 bits */
   typedef int             Zone1_t;
   typedef int          Bitchunk_t;
   typedef int               U16_t;
   typedef int         _mnx_Mode_t;
   
   #endif /* _EM_WSIZE == 2, etc */
    
   /* Signal handler type, e.g. SIG_IGN */
   typedef void _PROTOTYPE( (*sighandler_t), (int) );
   
   /* Compatibility with other systems */
   typedef unsigned char   u_char;
   typedef unsigned short  u_short;
   typedef unsigned int    u_int;
   typedef unsigned long   u_long;
   typedef char            *caddr_t;
   
   #endif /* _TYPES_H */

Cache object: c9536788b5a1355bed1b414f09d18b6e