Fix redundant formatting macros

[thirdparty/man-pages.git] / man3 / timeradd.3

.\" Copyright (c) 2007 by Michael Kerrisk <mtk.manpages@gmail.com>
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.\" 2007-07-31, mtk, Created
.\"
.TH TIMERADD 3 2007-07-31 "Linux" "Linux Programmer's Manual"
.SH NAME
timeradd, timersub, timercmp, timerclear, timerisset \- timeval operations
.SH SYNOPSIS
.nf
.B #include <sys/time.h>

.BI "void timeradd(struct timeval *" a ", struct timeval *" b ,
.BI "              struct timeval *" res );

.BI "void timersub(struct timeval *" a ", struct timeval *" b ,
.BI "              struct timeval *" res );

.BI "void timerclear(struct timeval *" tvp );

.BI "void timerisset(struct timeval *" tvp );

.BI "void timercmp(struct timeval *" a ", struct timeval *" b ", " CMP );
.fi
.sp
.in -4n
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.in
.sp
All functions shown above require:
_BSD_SOURCE
.SH DESCRIPTION
The macros are provided to operate on
.I timeval
structures, defined in
.I <sys/time.h>
as:
.sp
.in +0.5i
.nf
struct timeval {
    time_t      tv_sec;     /* seconds */
    suseconds_t tv_usec;    /* microseconds */
};
.fi
.PP
.BR timeradd ()
adds the time values in
.I a
and
.IR b ,
and places the sum in the
.I timeval
pointed to by
.IR res .
The result is normalized such that
.I res->tv_usec
has a value in the range 0 to 999,999.

.BR timersub ()
subtracts the time value in
.I b
from the time value in
.IR a ,
and places the result in the
.I timeval
pointed to by
.IR res .
The result is normalized such that
.I res->tv_usec
has a value in the range 0 to 999,999.

.BR timerclear ()
zeroes out the
.I timeval
structure pointed to by
.IR tvp ,
so that it represents the time at midnight
on the morning of 1 January 1970 (the Epoch).

.BR timerisset ()
returns true (non-zero) if either field of the
.I timeval
structure pointed to by
.I tvp
contains a non-zero value.

.BR timercmp ()
compares the timer values in
.I a
and
.I b
using the comparison operator
.IR CMP ,
and returns true (non-zero) or false (0) depending on
the result of the comparison.
.SH RETURN VALUE
.BR timerisset ()
and
.BR timercmp ()
return true (non-zero) or false (0).
.BR
.SH ERRORS
No errors are defined.
.SH CONFORMING TO
Not in POSIX.1-2001.
Present on most BSD derivatives.
.SH "SEE ALSO"
.BR gettimeofday (2),
.BR time (7).