sched_setattr.2: Minor tweaks to Claudio Scordino's patch

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

.\" Copyright (c) 1993 Michael Haardt
.\" (michael@moria.de)
.\" Fri Apr  2 11:32:09 MET DST 1993
.\"
.\" %%%LICENSE_START(GPLv2+_DOC_FULL)
.\" This is free documentation; you can redistribute it and/or
.\" modify it under the terms of the GNU General Public License as
.\" published by the Free Software Foundation; either version 2 of
.\" the License, or (at your option) any later version.
.\"
.\" The GNU General Public License's references to "object code"
.\" and "executables" are to be interpreted as the output of any
.\" document formatting or typesetting system, including
.\" intermediate and printed output.
.\"
.\" This manual is distributed in the hope that it will be useful,
.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
.\" GNU General Public License for more details.
.\"
.\" You should have received a copy of the GNU General Public
.\" License along with this manual; if not, see
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.\" %%%LICENSE_END
.\"
.\" Modified Sat Jul 24 14:23:14 1993 by Rik Faith (faith@cs.unc.edu)
.\" Modified Sun Oct 18 17:31:43 1998 by Andries Brouwer (aeb@cwi.nl)
.\" 2008-06-23, mtk, minor rewrites, added some details
.\"
.TH FTIME 3 2017-09-15 "GNU" "Linux Programmer's Manual"
.SH NAME
ftime \- return date and time
.SH SYNOPSIS
.B "#include <sys/timeb.h>"
.PP
.BI "int ftime(struct timeb *" tp );
.SH DESCRIPTION
This function returns the current time as seconds and milliseconds
since the Epoch, 1970-01-01 00:00:00 +0000 (UTC).
The time is returned in
.IR tp ,
which is declared as follows:
.PP
.in +4n
.EX
struct timeb {
    time_t         time;
    unsigned short millitm;
    short          timezone;
    short          dstflag;
};
.EE
.in
.PP
Here \fItime\fP is the number of seconds since the Epoch,
and \fImillitm\fP is the number of milliseconds since \fItime\fP
seconds since the Epoch.
The \fItimezone\fP field is the local timezone measured in minutes
of time west of Greenwich (with a negative value indicating minutes
east of Greenwich).
The \fIdstflag\fP field
is a flag that, if nonzero, indicates that Daylight Saving time
applies locally during the appropriate part of the year.
.PP
POSIX.1-2001 says that the contents of the \fItimezone\fP and \fIdstflag\fP
fields are unspecified; avoid relying on them.
.SH RETURN VALUE
This function always returns 0.
(POSIX.1-2001 specifies, and some systems document, a \-1 error return.)
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.TS
allbox;
lb lb lb
l l l.
Interface	Attribute	Value
T{
.BR ftime ()
T}	Thread safety	MT-Safe
.TE
.SH CONFORMING TO
4.2BSD, POSIX.1-2001.
POSIX.1-2008 removes the specification of
.BR ftime ().
.PP
This function is obsolete.
Don't use it.
If the time in seconds
suffices,
.BR time (2)
can be used;
.BR gettimeofday (2)
gives microseconds;
.BR clock_gettime (2)
gives nanoseconds but is not as widely available.
.SH BUGS
.PP
Early glibc2 is buggy and returns 0 in the
.I millitm
field;
glibc 2.1.1 is correct again.
.\" .SH HISTORY
.\" The
.\" .BR ftime ()
.\" function appeared in 4.2BSD.
.SH SEE ALSO
.BR gettimeofday (2),
.BR time (2)