NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | STANDARDS | HISTORY | SEE ALSO | COLOPHON |
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timeradd(3) Library Functions Manual timeradd(3)
timeradd, timersub, timercmp, timerclear, timerisset - timeval operations
Standard C library (libc, -lc)
#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); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): All functions shown above: Since glibc 2.19: _DEFAULT_SOURCE glibc 2.19 and earlier: _BSD_SOURCE
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 normalized 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 Epoch: 1970-01-01 00:00:00 +0000 (UTC). timerisset() returns true (nonzero) if either field of the timeval structure pointed to by tvp contains a nonzero value. timercmp() compares the timer values in a and b using the comparison operator CMP, and returns true (nonzero) or false (0) depending on the result of the comparison. Some systems (but not Linux/glibc), have a broken timercmp() implementation, in which CMP of >=, <=, and == do not work; portable applications can instead use !timercmp(..., <) !timercmp(..., >) !timercmp(..., !=)
timerisset() and timercmp() return true (nonzero) or false (0).
No errors are defined.
None.
BSD.
gettimeofday(2), time(7)
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Linux man-pages 6.9.1 2024-05-02 timeradd(3)
Pages that refer to this page: gettimeofday(2), timeval(3type), time(7)