TIMERADD(3)		   Linux Programmers Manual		  TIMERADD(3)



NAME
       timeradd,  timersub,  timercmp, timerclear, timerisset - timeval opera
       tions

SYNOPSIS
       #include 

       void timeradd(struct timeval *a, struct timeval *b,
		     struct timeval *res);

       void timersub(struct timeval *a, struct timeval *b,
		     struct timeval *res);

       void timerclear(struct timeval *tvp);

       void timerisset(struct timeval *tvp);

       void timercmp(struct timeval *a, struct timeval *b, CMP);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       All functions shown above: _BSD_SOURCE

DESCRIPTION
       The macros are provided to operate on timeval  structures,  defined  in
        as:

	   struct timeval {
	       time_t	   tv_sec;     /* seconds */
	       suseconds_t tv_usec;    /* microseconds */
	   };

       timeradd()  adds  the time values in a and b, and places the sum in the
       timeval pointed	to  by	res.   The  result  is	normalized  such  that
       res->tv_usec has a value in the range 0 to 999,999.

       timersub()  subtracts the time value in b from the time value in a, and
       places the result in the timeval pointed to by res.  The result is nor
       malized such that res->tv_usec has a value in the range 0 to 999,999.

       timerclear() zeros out the timeval structure pointed to by tvp, so that
       it represents the time at midnight on the morning  of  1  January  1970
       (the Epoch).

       timerisset()  returns  true  (non-zero)	if either field of the timeval
       structure pointed to by tvp contains a non-zero value.

       timercmp() compares the timer values in a and b	using  the  comparison
       operator CMP, and returns true (non-zero) or false (0) depending on the
       result of the comparison.

RETURN VALUE
       timerisset() and timercmp() return true (non-zero) or false (0).

ERRORS
       No errors are defined.

CONFORMING TO
       Not in POSIX.1-2001.  Present on most BSD derivatives.

SEE ALSO
       gettimeofday(2), time(7)

COLOPHON
       This page is part of release 3.05 of the Linux  man-pages  project.   A
       description  of	the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.



Linux				  2007-07-31			   TIMERADD(3)