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man:timerisset

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);
     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

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() 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(..., !=)

RETURN VALUE

     timerisset() and timercmp() return true (nonzero) or false (0).

ERRORS

     No errors are defined.

CONFORMING TO

     Not in POSIX.1.  Present on most BSD derivatives.

SEE ALSO

     gettimeofday(2), time(7)

COLOPHON

     This  page  is  part of release 4.16 of the Linux man-pages project.  A
     description of the project, information about reporting bugs,  and  the
     latest     version     of     this    page,    can    be    found    at
     https://www.kernel.org/doc/man-pages/.

Linux 2017-09-15 TIMERADD(3)

/data/webs/external/dokuwiki/data/pages/man/timerisset.txt · Last modified: 2019/05/17 09:47 by 127.0.0.1

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