diff --git a/src/DriverGMF/CMakeLists.txt b/src/DriverGMF/CMakeLists.txt
index f21111175..b79f94b12 100644
--- a/src/DriverGMF/CMakeLists.txt
+++ b/src/DriverGMF/CMakeLists.txt
@@ -61,7 +61,7 @@ SET(MeshDriverGMF_SOURCES
   DriverGMF_Read.cxx
   DriverGMF_Write.cxx
   DriverGMF.cxx
-  libmesh5.c
+  libmesh5.cxx
 )
 
 # --- rules ---
diff --git a/src/DriverGMF/libmesh5.c b/src/DriverGMF/libmesh5.cxx
similarity index 99%
rename from src/DriverGMF/libmesh5.c
rename to src/DriverGMF/libmesh5.cxx
index 82586efb4..c2d69301e 100644
--- a/src/DriverGMF/libmesh5.c
+++ b/src/DriverGMF/libmesh5.cxx
@@ -217,7 +217,7 @@ int GmfOpenMesh(const char *FilNam, int mod, ...)
                         break;
                 }
 
-        if( !MshIdx || !(msh = calloc(1, sizeof(GmfMshSct))) )
+        if( !MshIdx || !(msh = static_cast<GmfMshSct*>(calloc(1, sizeof(GmfMshSct)))) )
                 return(0);
 
         /* Copy the FilNam into the structure */