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Diffstat (limited to 'man/man3/difftime.3')
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diff --git a/man/man3/difftime.3 b/man/man3/difftime.3 new file mode 100644 index 0000000000..91ce56544b --- /dev/null +++ b/man/man3/difftime.3 @@ -0,0 +1,69 @@ +.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.\" References consulted: +.\" Linux libc source code +.\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) +.\" 386BSD man pages +.\" Modified Sat Jul 24 19:48:17 1993 by Rik Faith (faith@cs.unc.edu) +.TH DIFFTIME 3 2021-03-22 "Linux man-pages (unreleased)" +.SH NAME +difftime \- calculate time difference +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.B #include <time.h> +.PP +.BI "double difftime(time_t " time1 ", time_t " time0 ); +.fi +.SH DESCRIPTION +The +.BR difftime () +function returns the number of seconds elapsed +between time \fItime1\fP and time \fItime0\fP, represented as a +.IR double . +Each of the times is specified in calendar time, which means its +value is a measurement (in seconds) relative to the +Epoch, 1970-01-01 00:00:00 +0000 (UTC). +.SH ATTRIBUTES +For an explanation of the terms used in this section, see +.BR attributes (7). +.ad l +.nh +.TS +allbox; +lbx lb lb +l l l. +Interface Attribute Value +T{ +.BR difftime () +T} Thread safety MT-Safe +.TE +.hy +.ad +.sp 1 +.SH STANDARDS +POSIX.1-2001, POSIX.1-2008, C89, C99, SVr4, 4.3BSD. +.SH NOTES +On a POSIX system, +.I time_t +is an arithmetic type, and one could just +define +.PP +.in +4n +.EX +#define difftime(t1,t0) (double)(t1 \- t0) +.EE +.in +.PP +when the possible overflow in the subtraction is not a concern. +.SH SEE ALSO +.BR date (1), +.BR gettimeofday (2), +.BR time (2), +.BR ctime (3), +.BR gmtime (3), +.BR localtime (3) |