The return value of CPLGetConfigOption() is volatile, and can be

rouault · rouault · commit 82a22f08861b · 2012-09-28T21:58:53.000+02:00
invalidated by a following call to CPLSetConfigOption(). Thus it needs
to be duplicated.
diff --git a/src/providers/gdal/qgsgdalprovider.cpp b/src/providers/gdal/qgsgdalprovider.cpp
@@ -1377,7 +1377,7 @@ QString QgsGdalProvider::buildPyramids( QList<QgsRasterPyramid> const & theRaste
   }
 
   // are we using Erdas Imagine external overviews?
-  const char* myConfigUseRRD = CPLGetConfigOption( "USE_RRD", "NO" );
+  char* myConfigUseRRD = strdup(CPLGetConfigOption( "USE_RRD", "NO" ));
   if ( theFormat == PyramidsErdas )
     CPLSetConfigOption( "USE_RRD", "YES" );
   else
@@ -1471,6 +1471,7 @@ QString QgsGdalProvider::buildPyramids( QList<QgsRasterPyramid> const & theRaste
       //emit drawingProgress( 0, 0 );
       // restore former USE_RRD config (Erdas)
       CPLSetConfigOption( "USE_RRD", myConfigUseRRD );
+      free(myConfigUseRRD);
       return "FAILED_NOT_SUPPORTED";
     }
     else
@@ -1487,6 +1488,7 @@ QString QgsGdalProvider::buildPyramids( QList<QgsRasterPyramid> const & theRaste
 
   // restore former USE_RRD config (Erdas)
   CPLSetConfigOption( "USE_RRD", myConfigUseRRD );
+  free(myConfigUseRRD);
 
   QgsDebugMsg( "Pyramid overviews built" );
 
