NAME

timeradd, timersub, timerclear, timerisset, timercmp — operations on timevals

SYNOPSIS

#include < sys/time.h>

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);

int
timerisset( struct timeval *tvp);

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

DESCRIPTION

These macros are provided for manipulating timeval structures for use with the gettimeofday(2) and settimeofday(2) calls. The structure is defined in < sys/time.h> as:

struct timeval { 
 long tv_sec;  /* seconds since Jan. 1, 1970 */ 
 long tv_usec; /* and microseconds */ 
};

timeradd() adds the time information stored in a to b and stores the resulting timeval in res. The results are simplified such that the value of res->tv_usec is always less than 1,000,000 (1 second).

timersub() subtracts the time information stored in b from a and stores the resulting timeval in res.

timerclear() initializes tvp to midnight (0 hour) January 1st, 1970 (the Epoch).

timerisset() returns true if tvp is set to any time value other than the Epoch.

timercmp() compares a to b using the comparison operator given in CMP, and returns the result of that comparison.

SEE ALSO

gettimeofday(2)

HISTORY

The timeradd() family of macros were imported from NetBSD 1.1, and appeared in FreeBSD 2.2.6.