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.Dd July 30, 2018 .Dt TIMERADD 3 .Os .Sh NAME .Nm timeradd , .Nm timersub , .Nm timerclear , .Nm timerisset , .Nm timercmp , .Nm timespecadd , .Nm timespecsub , .Nm timespecclear , .Nm timespecisset , .Nm timespeccmp .Nd operations on timevals and timespecs .Sh SYNOPSIS n sys/time.h .Ft void .Fn timeradd "struct timeval *a" "struct timeval *b" "struct timeval *res" .Ft void .Fn timersub "struct timeval *a" "struct timeval *b" "struct timeval *res" .Ft void .Fn timerclear "struct timeval *tvp" .Ft int .Fn timerisset "struct timeval *tvp" .Ft int .Fn timercmp "struct timeval *a" "struct timeval *b" CMP .Ft void .Fn timespecadd "struct timespec *a" "struct timespec *b" "struct timespec *res" .Ft void .Fn timespecsub "struct timespec *a" "struct timespec *b" "struct timespec *res" .Ft void .Fn timespecclear "struct timespec *ts" .Ft int .Fn timespecisset "struct timespec *ts" .Ft int .Fn timespeccmp "struct timespec *a" "struct timespec *b" CMP .Sh DESCRIPTION These macros are provided for manipulating .Fa timeval and .Fa timespec structures for use with the .Xr clock_gettime 2 , .Xr clock_settime 2 , .Xr gettimeofday 2 and .Xr settimeofday 2 calls. The .Fa timeval structure is defined in n sys/time.h as: d -literal struct timeval { long tv_sec; /* seconds since Jan. 1, 1970 */ long tv_usec; /* and microseconds */ }; .Ed And the .Fa timespec structure is defined in n time.h as: d -literal struct timespec { time_t tv_sec; /* seconds */ long tv_nsec; /* and nanoseconds */ }; .Ed
p .Fn timeradd and .Fn timespecadd add the time information stored in .Fa a to .Fa b and store the result in .Fa res . The results are simplified such that the value of .Fa res->tv_usec or .Fa res->tv_nsec is always less than 1 second.
p .Fn timersub and .Fn timespecsub subtract the time information stored in .Fa b from .Fa a and store the result in .Fa res .
p .Fn timerclear and .Fn timespecclear initialize their argument to midnight (0 hour) January 1st, 1970 (the Epoch).
p .Fn timerisset and .Fn timespecisset return true if their argument is set to any time value other than the Epoch.
p .Fn timercmp and .Fn timespeccmp compare .Fa a to .Fa b using the comparison operator given in .Fa CMP , and return the result of that comparison. .Sh SEE ALSO .Xr gettimeofday 2 , .Xr clock_gettime 2 .Sh HISTORY The .Fn timeradd family of macros were imported from .Nx 1.1 , and appeared in .Fx 2.2.6 . The .Fn timespecadd family of macros were imported from .Nx 1.3 into .Fx 3.0 , though they were not exposed to userland until .Fx 12.0 .