[gnumeric] NOW: use 1us resolution.

[Morten Welinder <mortenw src gnome org>]

commit fe3826b0358024e16e96ae8eae4e5b90efccb92e
Author: Morten Welinder <terra gnome org>
Date:   Fri Dec 18 14:26:33 2020 -0500

    NOW: use 1us resolution.
    
    Implementation isn't elegant.  The guts are in goffice and we might
    need an extra api for this.

 NEWS                        | 1 +
 plugins/fn-date/ChangeLog   | 4 ++++
 plugins/fn-date/functions.c | 5 ++++-
 3 files changed, 9 insertions(+), 1 deletion(-)
---
diff --git a/NEWS b/NEWS
index c5199ccb2..f13fdd656 100644
--- a/NEWS
+++ b/NEWS
@@ -13,6 +13,7 @@ Morten:
        * Improve handling of expressions in csv files.
        * Plug ssconvert leak.  [#546]
        * Fix bogus time match for "3.a".  [#545]
+       * Use 1us resolution for NOW.  [#549]
 
 --------------------------------------------------------------------------
 Gnumeric 1.12.48
diff --git a/plugins/fn-date/ChangeLog b/plugins/fn-date/ChangeLog
index 897bfc9e9..6ca89612b 100644
--- a/plugins/fn-date/ChangeLog
+++ b/plugins/fn-date/ChangeLog
@@ -1,3 +1,7 @@
+2020-12-18  Morten Welinder  <terra gnome org>
+
+       * functions.c (gnumeric_now): Use 1us resolution.
+
 2020-08-12  Morten Welinder <terra gnome org>
 
        * Release 1.12.48
diff --git a/plugins/fn-date/functions.c b/plugins/fn-date/functions.c
index feff232cc..206ab1fa9 100644
--- a/plugins/fn-date/functions.c
+++ b/plugins/fn-date/functions.c
@@ -410,7 +410,10 @@ static GnmFuncHelp const help_now[] = {
 static GnmValue *
 gnumeric_now (GnmFuncEvalInfo *ei, G_GNUC_UNUSED GnmValue const * const *argv)
 {
-       return value_new_float (go_date_timet_to_serial_raw (time (NULL), DATE_CONV (ei->pos)));
+       guint64 t = g_get_real_time ();
+       double r = go_date_timet_to_serial_raw (t / 1000000, DATE_CONV (ei->pos));
+       r += (t % 1000000) / (24 * 60 * 60 * 1000000.0);
+       return value_new_float (r);
 }
 
 /***************************************************************************/