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+'\" t
+.\" Copyright (C) 2001 Andries Brouwer <aeb@cwi.nl>
+.\"
+.\" SPDX-License-Identifier: Linux-man-pages-copyleft
+.\"
+.TH timegm 3 2023-07-20 "Linux man-pages 6.05.01"
+.SH NAME
+timegm, timelocal \- inverses of gmtime and localtime
+.SH LIBRARY
+Standard C library
+.RI ( libc ", " \-lc )
+.SH SYNOPSIS
+.nf
+.B #include <time.h>
+.PP
+.BI "[[deprecated]] time_t timelocal(struct tm *" tm );
+.BI "time_t timegm(struct tm *" tm );
+.PP
+.fi
+.RS -4
+Feature Test Macro Requirements for glibc (see
+.BR feature_test_macros (7)):
+.RE
+.PP
+.BR timelocal (),
+.BR timegm ():
+.nf
+ Since glibc 2.19:
+ _DEFAULT_SOURCE
+ glibc 2.19 and earlier:
+ _BSD_SOURCE || _SVID_SOURCE
+.fi
+.SH DESCRIPTION
+The functions
+.BR timelocal ()
+and
+.BR timegm ()
+are the inverses of
+.BR localtime (3)
+and
+.BR gmtime (3).
+Both functions take a broken-down time and convert it to calendar time
+(seconds since the Epoch, 1970-01-01 00:00:00 +0000, UTC).
+The difference between the two functions is that
+.BR timelocal ()
+takes the local timezone into account when doing the conversion, while
+.BR timegm ()
+takes the input value to be Coordinated Universal Time (UTC).
+.SH RETURN VALUE
+On success,
+these functions return the calendar time (seconds since the Epoch),
+expressed as a value of type
+.IR time_t .
+On error, they return the value
+.I (time_t)\ \-1
+and set
+.I errno
+to indicate the error.
+.SH ERRORS
+.TP
+.B EOVERFLOW
+The result cannot be represented.
+.SH ATTRIBUTES
+For an explanation of the terms used in this section, see
+.BR attributes (7).
+.TS
+allbox;
+lbx lb lb
+l l l.
+Interface Attribute Value
+T{
+.na
+.nh
+.BR timelocal (),
+.BR timegm ()
+T} Thread safety MT-Safe env locale
+.TE
+.sp 1
+.SH STANDARDS
+BSD.
+.SH HISTORY
+GNU, BSD.
+.PP
+The
+.BR timelocal ()
+function is equivalent to the POSIX standard function
+.BR mktime (3).
+There is no reason to ever use it.
+.SH SEE ALSO
+.BR gmtime (3),
+.BR localtime (3),
+.BR mktime (3),
+.BR tzset (3)