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NAME

       sys/types.h - data types

SYNOPSIS

       #include <sys/types.h>

DESCRIPTION

       The  <sys/types.h>  header  shall  include definitions for at least the
       following types:

       blkcnt_t
              Used for file block counts.

       blksize_t
              Used for block sizes.

       clock_t
              Used for system times in  clock  ticks  or  CLOCKS_PER_SEC;  see
              <time.h> .

       clockid_t
              Used for clock ID type in the clock and timer functions.

       dev_t  Used for device IDs.

       fsblkcnt_t
              Used for file system block counts.

       fsfilcnt_t
              Used for file system file counts.

       gid_t  Used for group IDs.

       id_t   Used  as a general identifier; can be used to contain at least a
              pid_t, uid_t, or gid_t.

       ino_t  Used for file serial numbers.

       key_t  Used for XSI interprocess communication.

       mode_t Used for some file attributes.

       nlink_t
              Used for link counts.

       off_t  Used for file sizes.

       pid_t  Used for process IDs and process group IDs.

       pthread_attr_t
              Used to identify a thread attribute object.

       pthread_barrier_t
              Used to identify a barrier.

       pthread_barrierattr_t
              Used to define a barrier attributes object.

       pthread_cond_t
              Used for condition variables.

       pthread_condattr_t
              Used to identify a condition attribute object.

       pthread_key_t
              Used for thread-specific data keys.

       pthread_mutex_t
              Used for mutexes.

       pthread_mutexattr_t
              Used to identify a mutex attribute object.

       pthread_once_t
              Used for dynamic package initialization.

       pthread_rwlock_t
              Used for read-write locks.

       pthread_rwlockattr_t
              Used for read-write lock attributes.

       pthread_spinlock_t
              Used to identify a spin lock.

       pthread_t
              Used to identify a thread.

       size_t Used for sizes of objects.

       ssize_t
              Used for a count of bytes or an error indication.

       suseconds_t
              Used for time in microseconds.

       time_t Used for time in seconds.

       timer_t
              Used for timer ID returned by timer_create().

       trace_attr_t
              Used to identify a trace stream attributes object.

       trace_event_id_t
              Used to identify a trace event type.

       trace_event_set_t
              Used to identify a trace event type set.

       trace_id_t
              Used to identify a trace stream.

       uid_t  Used for user IDs.

       useconds_t
              Used for time in microseconds.

       All of the types shall be defined as arithmetic types of an appropriate
       length, with the following exceptions:

       key_t

       pthread_attr_t

       pthread_barrier_t
       pthread_barrierattr_t

       pthread_cond_t
       pthread_condattr_t
       pthread_key_t
       pthread_mutex_t
       pthread_mutexattr_t
       pthread_once_t
       pthread_rwlock_t
       pthread_rwlockattr_t

       pthread_spinlock_t

       trace_attr_t
       trace_event_id_t

       trace_event_set_t

       trace_id_t

       Additionally:

        * mode_t shall be an integer type.

        * nlink_t, uid_t, gid_t, and id_t shall be integer types.

        * blkcnt_t and off_t shall be signed integer types.

        * fsblkcnt_t,  fsfilcnt_t,    and  ino_t  shall be defined as unsigned
          integer types.

        * size_t shall be an unsigned integer type.

        * blksize_t, pid_t, and ssize_t shall be signed integer types.

        * time_t and clock_t shall be integer or real-floating types.

       The type ssize_t shall be capable of storing values  at  least  in  the
       range  [-1, {SSIZE_MAX}].     The  type useconds_t shall be an unsigned
       integer  type  capable  of  storing  values  at  least  in  the   range
       [0, 1000000].  The  type  suseconds_t  shall  be  a signed integer type
       capable of storing values at least in the range [-1, 1000000].

       The implementation shall support one or more  programming  environments
       in  which the widths of blksize_t, pid_t, size_t, ssize_t, suseconds_t,
       and useconds_t are no greater than the width of type long. The names of
       these  programming  environments  can  be  obtained using the confstr()
       function or the getconf utility.

       There are  no  defined  comparison  or  assignment  operators  for  the
       following types:

       pthread_attr_t

       pthread_barrier_t
       pthread_barrierattr_t

       pthread_cond_t
       pthread_condattr_t
       pthread_mutex_t
       pthread_mutexattr_t
       pthread_rwlock_t
       pthread_rwlockattr_t

       pthread_spinlock_t

       trace_attr_t

       The following sections are informative.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       <time.h>  ,  the  System  Interfaces  volume  of  IEEE Std 1003.1-2001,
       confstr(), the Shell  and  Utilities  volume  of  IEEE Std 1003.1-2001,
       getconf

COPYRIGHT

       Portions  of  this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
       Specifications Issue 6, Copyright (C) 2001-2003  by  the  Institute  of
       Electrical  and  Electronics  Engineers, Inc and The Open Group. In the
       event of any discrepancy between this version and the original IEEE and
       The  Open Group Standard, the original IEEE and The Open Group Standard
       is the referee document. The original Standard can be  obtained  online
       at http://www.opengroup.org/unix/online.html .