[PATCH] strftime.3: document how %z and %Z are calculated

[Paul Eggert <eggert@xxxxxxxxxxx>]

---
 man3/strftime.3 | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/man3/strftime.3 b/man3/strftime.3
index 57b2a38aa..90248d0b4 100644
--- a/man3/strftime.3
+++ b/man3/strftime.3
@@ -417,6 +417,8 @@ The
 or
 .I \-hhmm
 numeric timezone (that is, the hour and minute offset from UTC). (SU)
+(Calculated from
+.IR tm_gmtoff .)
 .TP
 .B %Z
 The timezone name or abbreviation.
@@ -427,6 +429,8 @@ The timezone name or abbreviation.
 The date and time in
 .BR date (1)
 format. (TZ)
+(Calculated from
+.IR tm_zone .)
 (Not supported in glibc2.)
 .TP
 .B %%
-- 
2.39.2