xenial (7) sys_time.h.7posix.gz

PROLOG

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of this interface
       may differ (consult the corresponding Linux manual page for details of Linux behavior), or the  interface
       may not be implemented on Linux.

NAME

       sys/time.h — time types

SYNOPSIS

       #include <sys/time.h>

DESCRIPTION

       The  <sys/time.h>  header  shall define the timeval structure, which shall include 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, which shall include at least the  following
       members:

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

       The <sys/time.h> header shall define the time_t and suseconds_t types as described in <sys/types.h>.

       The <sys/time.h> header shall define the fd_set type as described in <sys/select.h>.

       The  <sys/time.h>  header  shall  define  the  following  symbolic  constants  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  <sys/time.h>  header  shall define the following 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   setitimer(int, const struct itimerval *restrict,
                     struct itimerval *restrict);
           int   select(int, fd_set *restrict, fd_set *restrict, fd_set *restrict,
                     struct timeval *restrict);
           int   utimes(const char *, const struct timeval [2]);

       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 POSIX.1‐2008, futimens(), getitimer(), gettimeofday(), pselect()

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition,
       Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open  Group  Base
       Specifications  Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc
       and The Open Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/online.html .

       Any  typographical  or formatting errors that appear in this page are most likely to have been introduced
       during  the  conversion  of  the  source  files  to  man  page  format.  To  report  such   errors,   see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .