LGTM: [skip ci] fix: Local variable hides global variable

A local variable or parameter that hides a global variable of the same name.
This may be confusing. Consider renaming one of the variables.

src/Gui/ViewProviderPyImp.cpp

@@ -34,6 +34,7 @@
 #include <Inventor/nodes/SoSeparator.h>
 #include <Inventor/nodes/SoSwitch.h>
 #include <Inventor/details/SoDetail.h>
+#include "SoFCDB.h"
 
 #include "ViewProvider.h"
 #include "WidgetFactory.h"
@@ -621,37 +622,10 @@ void  ViewProviderPy::setSwitchNode(Py::Object)
 
 }
 
-static char * buffer;
-static size_t buffer_size = 0;
-
-static void *
-buffer_realloc(void * bufptr, size_t size)
-{
-    buffer = (char *)realloc(bufptr, size);
-    buffer_size = size;
-    return buffer;
-}
-
-static SbString
-buffer_writeaction(SoNode * root)
-{
-    SoOutput out;
-    buffer = (char *)malloc(1024);
-    buffer_size = 1024;
-    out.setBuffer(buffer, buffer_size, buffer_realloc);
-
-    SoWriteAction wa(&out);
-    wa.apply(root);
-
-    SbString s(buffer);
-    free(buffer);
-    return s;
-}
-
 Py::String ViewProviderPy::getIV(void) const
 {
-    SbString buf = buffer_writeaction(getViewProviderPtr()->getRoot());
-    return Py::String(buf.getString());
+    std::string buf = Gui::SoFCDB::writeNodesToString(getViewProviderPtr()->getRoot());
+    return Py::String(buf);
 }
 
 Py::Object ViewProviderPy::getIcon(void) const