diff --git a/definitions/mars/grib.ocda.tpa.def b/definitions/mars/grib.ocda.tpa.def
index d46a8bd2a..d9c2ce22f 100644
--- a/definitions/mars/grib.ocda.tpa.def
+++ b/definitions/mars/grib.ocda.tpa.def
@@ -6,3 +6,6 @@ alias mars.time = dataTime;
 
 unalias mars.step;
 alias mars.step = stepRange;
+if (defined(perturbationNumber)) {
+ alias mars.number = perturbationNumber;
+}
diff --git a/src/grib_dumper_class_grib_encode_C.cc b/src/grib_dumper_class_grib_encode_C.cc
index 91d07b688..5ecb6953d 100644
--- a/src/grib_dumper_class_grib_encode_C.cc
+++ b/src/grib_dumper_class_grib_encode_C.cc
@@ -342,7 +342,7 @@ static void dump_values(grib_dumper* d, grib_accessor* a)
     fprintf(self->dumper.out, "    size = %zu;\n", size);
     fprintf(self->dumper.out, "    v%s    = (%s*)calloc(size,sizeof(%s));\n", stype, stype, stype);
     fprintf(self->dumper.out, "    if(!v%s) {\n", stype);
-    fprintf(self->dumper.out, "        fprintf(stderr,\"failed to allocate %%d bytes\\n\",size*sizeof(%s));\n", stype);
+    fprintf(self->dumper.out, "        fprintf(stderr,\"failed to allocate %%zu bytes\\n\",size*sizeof(%s));\n", stype);
     fprintf(self->dumper.out, "        exit(1);\n");
     fprintf(self->dumper.out, "    }\n");