<s>
The	O
C	B-Language
date	I-Language
and	I-Language
time	I-Language
functions	I-Language
are	O
a	O
group	O
of	O
functions	O
in	O
the	O
standard	B-Language
library	I-Language
of	O
the	O
C	B-Language
programming	I-Language
language	I-Language
implementing	O
date	O
and	O
time	B-Operating_System
manipulation	O
operations	O
.	O
</s>
<s>
They	O
provide	O
support	O
for	O
time	B-Operating_System
acquisition	O
,	O
conversion	O
between	O
date	O
formats	O
,	O
and	O
formatted	O
output	O
to	O
strings	O
.	O
</s>
<s>
The	O
C	B-Language
date	I-Language
and	I-Language
time	I-Language
operations	I-Language
are	O
defined	O
in	O
the	O
time.h	B-Language
header	B-Language
file	I-Language
(	O
ctime	O
header	O
in	O
C++	B-Language
)	O
.	O
</s>
<s>
Identifier	O
Description	O
Timemanipulation	O
difftime	O
computes	O
the	O
difference	O
in	O
seconds	O
between	O
two	O
time_t	O
values	O
time	B-Operating_System
returns	O
the	O
current	O
time	B-Operating_System
of	I-Operating_System
the	I-Operating_System
system	I-Operating_System
as	O
a	O
time_t	O
value	O
,	O
number	O
of	O
seconds	O
,	O
(	O
which	O
is	O
usually	O
time	B-Operating_System
since	O
an	O
epoch	O
,	O
typically	O
the	O
Unix	B-Operating_System
epoch	I-Operating_System
)	O
.	O
</s>
<s>
See	O
RFC	O
868	O
.	O
clock	O
returns	O
a	O
processor	O
tick	O
count	O
associated	O
with	O
the	O
process	O
timespec_get	O
(	O
C11	O
)	O
returns	O
a	O
calendar	B-Application
time	B-Operating_System
based	O
on	O
a	O
time	B-Operating_System
base	O
Formatconversions	O
asctime	O
converts	O
a	O
struct	O
tm	O
object	O
to	O
a	O
textual	O
representation	O
(	O
deprecated	O
)	O
ctime	O
converts	O
a	O
time_t	O
value	O
to	O
a	O
textual	O
representation	O
strftime	O
converts	O
a	O
struct	O
tm	O
object	O
to	O
custom	O
textual	O
representation	O
strptime	O
converts	O
a	O
string	O
with	O
time	B-Operating_System
information	O
to	O
a	O
struct	O
tm	O
wcsftime	O
converts	O
a	O
struct	O
tm	O
object	O
to	O
custom	O
wide	O
string	O
textual	O
representation	O
gmtime	O
converts	O
a	O
time_t	O
value	O
to	O
calendar	B-Application
time	B-Operating_System
expressed	O
as	O
Coordinated	O
Universal	O
Timeopen-std.org	O
-	O
Committee	O
Draft	O
--	O
May	O
6	O
,	O
2005	O
page	O
355	O
localtime	O
converts	O
a	O
time_t	O
value	O
to	O
calendar	B-Application
time	B-Operating_System
expressed	O
as	O
local	O
time	B-Operating_System
mktime	O
converts	O
calendar	B-Application
time	B-Operating_System
to	O
a	O
time_t	O
value	O
.	O
</s>
<s>
The	O
and	O
related	O
types	O
were	O
originally	O
proposed	O
by	O
Markus	O
Kuhn	O
to	O
provide	O
a	O
variety	O
of	O
time	B-Operating_System
bases	O
,	O
but	O
only	O
was	O
accepted	O
.	O
</s>
<s>
The	O
functionalities	O
were	O
,	O
however	O
,	O
added	O
to	O
C++	B-Language
in	O
2020	O
in	O
std::chrono	O
.	O
</s>
<s>
The	O
following	O
C	B-Language
source	O
code	O
prints	O
the	O
current	O
time	B-Operating_System
to	O
the	O
standard	B-Operating_System
output	I-Operating_System
stream	I-Operating_System
.	O
</s>
