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TIMERADD(3) Linux Programmer's Manual TIMERADD(3) NAME timeradd, timersub, timercmp, timerclear, timerisset - timeval opera- tions 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); 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 require: _BSD_SOURCE DESCRIPTION The macros are provided to operate on timeval structures, defined in <sys/time.h> 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() zeroes 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). Linux 2007-07-31 TIMERADD(3)