From 536025791ac8ea532b952529e88913c5a1ab56fd Mon Sep 17 00:00:00 2001
From: Paul Cornett <paulcor@users.noreply.github.com>
Date: Sun, 25 Aug 2019 23:08:59 -0700
Subject: [PATCH] Avoid converting empty strings to NULL pointers in
 non-Unicode build

...when using utf8_str() or wxGTK_CONV as argument to const char* function parameter
---
 include/wx/string.h  | 6 +++++-
 src/gtk/utilsgtk.cpp | 5 ++++-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/include/wx/string.h b/include/wx/string.h
index a5a3b3108a..6e579ed616 100644
--- a/include/wx/string.h
+++ b/include/wx/string.h
@@ -1709,7 +1709,11 @@ public:
       { return FromUTF8Unchecked(utf8.c_str(), utf8.length()); }
 #endif
     const wxScopedCharBuffer utf8_str() const
-      { return wxMBConvUTF8().cWC2MB(wc_str()); }
+    {
+        if (empty())
+            return wxScopedCharBuffer::CreateNonOwned("", 0);
+        return wxMBConvUTF8().cWC2MB(wc_str());
+    }
 #endif
 
     const wxScopedCharBuffer ToUTF8() const { return utf8_str(); }
diff --git a/src/gtk/utilsgtk.cpp b/src/gtk/utilsgtk.cpp
index 137fb2cf16..4a7afc9edc 100644
--- a/src/gtk/utilsgtk.cpp
+++ b/src/gtk/utilsgtk.cpp
@@ -86,6 +86,9 @@ wxWindow* wxFindWindowAtPoint(const wxPoint& pt)
 WXDLLIMPEXP_CORE wxCharBuffer
 wxConvertToGTK(const wxString& s, wxFontEncoding enc)
 {
+    if (s.empty())
+        return wxCharBuffer("");
+
     wxWCharBuffer wbuf;
     if ( enc == wxFONTENCODING_SYSTEM || enc == wxFONTENCODING_DEFAULT )
     {
@@ -96,7 +99,7 @@ wxConvertToGTK(const wxString& s, wxFontEncoding enc)
         wbuf = wxCSConv(enc).cMB2WC(s.c_str());
     }
 
-    if ( !wbuf && !s.empty() )
+    if (wbuf.length() == 0)
     {
         // conversion failed, but we still want to show something to the user
         // even if it's going to be wrong it is better than nothing