Give wxSafeYield an onlyIfNeeded parameter

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@18278 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/latex/wx/function.tex

@@ -371,7 +371,8 @@ call to this function.
 
 \membersection{::wxSafeYield}\label{wxsafeyield}
 
-\func{bool}{wxSafeYield}{\param{wxWindow*}{ win = NULL}}
+\func{bool}{wxSafeYield}{\param{wxWindow*}{ win = NULL}, \param{bool}{
+    onlyIfNeeded = FALSE}}
 
 This function is similar to wxYield, except that it disables the user input to
 all program windows before calling wxYield and re-enables it again

include/wx/utils.h

@@ -370,7 +370,7 @@ WXDLLEXPORT bool wxYield();
 WXDLLEXPORT bool wxYieldIfNeeded();
 
 // Yield to other apps/messages and disable user input
-WXDLLEXPORT bool wxSafeYield(wxWindow *win = NULL);
+WXDLLEXPORT bool wxSafeYield(wxWindow *win = NULL, bool onlyIfNeeded = FALSE);
 
 // Enable or disable input to all top level windows
 WXDLLEXPORT void wxEnableTopLevelWindows(bool enable = TRUE);

src/common/utilscmn.cpp

@@ -872,10 +872,13 @@ wxWindowDisabler::~wxWindowDisabler()
 
 // Yield to other apps/messages and disable user input to all windows except
 // the given one
-bool wxSafeYield(wxWindow *win)
+bool wxSafeYield(wxWindow *win, bool onlyIfNeeded = FALSE)
 {
     wxWindowDisabler wd(win);
 
+    if (onlyIfNeeded)
+        bool rc = wxYieldIfNeeded();
+    else
         bool rc = wxYield();
 
     return rc;