added wxTempFile::Flush() (dedicated to Theodore Ts'o and Ext4)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@60830 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/changes.txt

@@ -330,6 +330,7 @@ All:
 
 - Added wxStd{Input,Output}Stream classes (Jonathan Liu).
 - Include port number in host header in wxHTTP (Marcin 'Malcom' Malich).
+- Added wxTempFile::Flush().
 
 All (GUI):
 

include/wx/file.h

@@ -197,6 +197,10 @@ public:
   bool Write(const wxString& str, const wxMBConv& conv = wxMBConvUTF8())
     { return m_file.Write(str, conv); }
 
+  // flush data: can be called before closing file to ensure that data was
+  // correctly written out
+  bool Flush() { return m_file.Flush(); }
+
   // different ways to close the file
     // validate changes and delete the old file of name m_strName
   bool Commit();

interface/wx/file.h

@@ -129,6 +129,18 @@ public:
     */
     void Discard();
 
+    /**
+        Flush the data written to the file to disk.
+
+        This simply calls wxFile::Flush() for the underlying file and may be
+        necessary with file systems such as XFS and Ext4 under Linux. Calling
+        this function may however have serious performance implications and
+        also is not necessary with many other file systems so it is not done by
+        default -- but you can call it before calling Commit() to absolutely
+        ensure that the data was indeed written to the disk correctly.
+     */
+    bool Flush();
+
     /**
         Returns @true if the file was successfully opened.
     */