Clarify QDateTime documentation re timeSpec conversion.

Clarify the documentation for setTimeSpec, toTimeSpec, toUTC and
toLocalTime, to be clear on which ones return the same point in time,
and which one simply changes the timezone.

Change-Id: Ic47dd8876ea733f1df0f64eca5bdf00d04f8d0d4
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

diff --git a/src/corelib/doc/snippets/code/src_corelib_tools_qdatetime.cpp b/src/corelib/doc/snippets/code/src_corelib_tools_qdatetime.cpp
index ce0ccc1..1a89d4d 100644 (file)
--- a/src/corelib/doc/snippets/code/src_corelib_tools_qdatetime.cpp
+++ b/src/corelib/doc/snippets/code/src_corelib_tools_qdatetime.cpp
@@ -156,4 +156,39 @@ qDebug() << "Days from startDate to endDate: " << startDate.daysTo(endDate);
 
 qSwap(startDate, endDate); // Make endDate before startDate.
 qDebug() << "Days from startDate to endDate: " << startDate.daysTo(endDate);
-//! [15]
\ No newline at end of file
+//! [15]
+
+//! [16]
+QDateTime local(QDateTime::currentDateTime());
+QDateTime UTC(local.toTimeSpec(Qt::UTC));
+qDebug() << "Local time is:" << local;
+qDebug() << "UTC time is:" << UTC;
+qDebug() << "No difference between times:" << local.secsTo(UTC);
+//! [16]
+
+//! [17]
+QDateTime UTC(QDateTime::currentDateTimeUtc());
+QDateTime local(UTC.toLocalTime());
+qDebug() << "UTC time is:" << UTC;
+qDebug() << "Local time is:" << local;
+qDebug() << "No difference between times:" << UTC.secsTo(local);
+//! [17]
+
+//! [18]
+QDateTime local(QDateTime::currentDateTime());
+QDateTime UTC(local.toUTC());
+qDebug() << "Local time is:" << local;
+qDebug() << "UTC time is:" << UTC;
+qDebug() << "No difference between times:" << local.secsTo(UTC);
+//! [18]
+
+//! [19]
+QDateTime local(QDateTime::currentDateTime());
+qDebug() << "Local time is:" << local;
+
+QDateTime UTC(local);
+UTC.setTimeSpec(Qt::UTC);
+qDebug() << "UTC time is:" << UTC;
+
+qDebug() << "There are" << local.secsTo(UTC) << "seconds difference between the datetimes.";
+//! [19]
\ No newline at end of file

diff --git a/src/corelib/tools/qdatetime.cpp b/src/corelib/tools/qdatetime.cpp
index 905055c..8accc32 100644 (file)
--- a/src/corelib/tools/qdatetime.cpp
+++ b/src/corelib/tools/qdatetime.cpp
@@ -2322,6 +2322,10 @@ void QDateTime::setTime(const QTime &time)
 
 /*!
     Sets the time specification used in this datetime to \a spec.
+    The datetime will refer to a different point in time.
+
+    Example:
+    \snippet code/src_corelib_tools_qdatetime.cpp 19
 
     \sa timeSpec(), setDate(), setTime(), Qt::TimeSpec
 */
@@ -2856,9 +2860,12 @@ qint64 QDateTime::msecsTo(const QDateTime &other) const
 /*!
     \fn QDateTime QDateTime::toTimeSpec(Qt::TimeSpec specification) const
 
-    Returns a copy of this datetime configured to use the given time
+    Returns a copy of this datetime converted to the given time
     \a specification.
 
+    Example:
+    \snippet code/src_corelib_tools_qdatetime.cpp 16
+
     \sa timeSpec(), toUTC(), toLocalTime()
 */
 
@@ -3570,6 +3577,10 @@ QDateTime QDateTime::fromString(const QString &string, const QString &format)
     Returns a datetime containing the date and time information in
     this datetime, but specified using the Qt::LocalTime definition.
 
+    Example:
+
+    \snippet code/src_corelib_tools_qdatetime.cpp 17
+
     \sa toTimeSpec()
 */
 
@@ -3579,6 +3590,10 @@ QDateTime QDateTime::fromString(const QString &string, const QString &format)
     Returns a datetime containing the date and time information in
     this datetime, but specified using the Qt::UTC definition.
 
+    Example:
+
+    \snippet code/src_corelib_tools_qdatetime.cpp 18
+
     \sa toTimeSpec()
 */