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-rw-r--r--lib/libc/stdtime/ctime.339
1 files changed, 33 insertions, 6 deletions
diff --git a/lib/libc/stdtime/ctime.3 b/lib/libc/stdtime/ctime.3
index 96b7f775535a..6384e8bd959b 100644
--- a/lib/libc/stdtime/ctime.3
+++ b/lib/libc/stdtime/ctime.3
@@ -27,7 +27,7 @@
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
-.Dd March 26, 2024
+.Dd September 23, 2025
.Dt CTIME 3
.Os
.Sh NAME
@@ -41,6 +41,8 @@
.Nm localtime ,
.Nm localtime_r ,
.Nm mktime ,
+.Nm offtime ,
+.Nm offtime_r ,
.Nm timegm
.Nd transform binary date and time values
.Sh LIBRARY
@@ -68,14 +70,19 @@
.Fn localtime_r "const time_t *clock" "struct tm *result"
.Ft time_t
.Fn mktime "struct tm *tm"
+.Ft struct tm *
+.Fn offtime "const time_t *clock" "long offset"
+.Ft struct tm *
+.Fn offtime_r "const time_t *clock" "long offset" "struct tm *result"
.Ft time_t
.Fn timegm "struct tm *tm"
.Sh DESCRIPTION
The
.Fn ctime ,
.Fn gmtime ,
+.Fn localtime ,
and
-.Fn localtime
+.Fn offtime
functions all take as argument a pointer to a time value representing
the time in seconds since the Epoch (00:00:00 UTC on January 1, 1970;
see
@@ -123,6 +130,18 @@ adjustment, and returns a pointer to a
.Vt struct tm .
.Pp
The
+.Fn offtime
+function similarly converts the time value with a time zone adjustment
+corresponding to the provided
+.Fa offset ,
+which is expressed in seconds, with positive values indicating a time
+zone ahead of UTC (east of the Prime Meridian).
+It does not call
+.Xr tzset 3
+or modify
+.Va tzname .
+.Pp
+The
.Fn ctime
function
adjusts the time value for the current time zone in the same manner as
@@ -155,13 +174,15 @@ except the caller must provide the output buffer
.Fa buf ,
which must be at least 26 characters long, to store the result in.
The
-.Fn localtime_r
+.Fn localtime_r ,
+.Fn gmtime_r ,
and
-.Fn gmtime_r
+.Fn offtime_r
functions provide the same functionality as
-.Fn localtime
+.Fn localtime ,
+.Fn gmtime ,
and
-.Fn gmtime
+.Fn offtime
respectively, except the caller must provide the output buffer
.Fa result .
.Pp
@@ -368,6 +389,12 @@ and
.Fn localtime_r
functions have been available since
.Fx 8.0 .
+The
+.Fn offtime
+and
+.Fn offtime_r
+functions were added in
+.Fx 15.0 .
.Sh BUGS
Except for
.Fn difftime ,