NAME

       sys/time.h - time types

SYNOPSIS

       #include <sys/time.h>

DESCRIPTION

       The  <sys/time.h>  header  shall  define  the timeval structure that includes at least the
       following members:

              time_t         tv_sec      Seconds.
              suseconds_t    tv_usec     Microseconds.

       The <sys/time.h> header shall define the itimerval structure that includes  at  least  the
       following members:

              struct timeval it_interval Timer interval.
              struct timeval it_value    Current value.

       The time_t and suseconds_t types shall be defined as described in <sys/types.h> .

       The fd_set type shall be defined as described in <sys/select.h> .

       The  <sys/time.h>  header  shall  define  the  following  values for the which argument of
       getitimer() and setitimer():

       ITIMER_REAL
              Decrements in real time.

       ITIMER_VIRTUAL
              Decrements in process virtual time.

       ITIMER_PROF
              Decrements both in process virtual time and when the system is running on behalf of
              the process.

       The  following  shall  be  defined  as  described  in <sys/select.h> : FD_CLR() FD_ISSET()
       FD_SET() FD_ZERO() FD_SETSIZE

       The following shall be declared as functions and may also be defined as  macros.  Function
       prototypes shall be provided.

              int   getitimer(int, struct itimerval *);
              int   gettimeofday(struct timeval *restrict, void *restrict);
              int   select(int, fd_set *restrict, fd_set *restrict, fd_set *restrict,
                        struct timeval *restrict);
              int   setitimer(int, const struct itimerval *restrict,
                        struct itimerval *restrict);
              int   utimes(const char *, const struct timeval [2]); (LEGACY )

       Inclusion  of the <sys/time.h> header may make visible all symbols from the <sys/select.h>
       header.

       The following sections are informative.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       <sys/select.h> , <sys/types.h> , the System  Interfaces  volume  of  IEEE Std 1003.1-2001,
       getitimer(), gettimeofday(), select(), setitimer()

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 .