Replace magic number with commented symbolic constant.

tests/deco2d_model.c

@@ -277,7 +277,7 @@ modelRun(struct model_config setup, MPI_Comm comm)
         gatherRedistSet: ;
       }
 #endif
-      varDesc[varIdx].code = 129 + (int)varIdx;
+      varDesc[varIdx].code = GRIB_USERDEF + (int)varIdx;
       vlistDefVarCode(vlistID, varDesc[varIdx].id, varDesc[varIdx].code);
       vlistDefVarDatatype(vlistID, varDesc[varIdx].id, setup.datatype);
     }

tests/simple_model.c

@@ -194,7 +194,7 @@ modelRun(struct model_config setup, MPI_Comm comm)
         varDesc[varIdx].partDesc = idxlist;
       }
 #endif
-      varDesc[varIdx].code = 129 + (int)varIdx;
+      varDesc[varIdx].code = GRIB_USERDEF + (int)varIdx;
       vlistDefVarCode(vlistID, varDesc[varIdx].id, varDesc[varIdx].code);
       vlistDefVarDatatype(vlistID, varDesc[varIdx].id, setup.datatype);
     }

tests/simple_model_helper.h

@@ -9,6 +9,12 @@
 #include <math.h>
 #include <time.h>
 
+
+enum {
+  /* 129 is the first user-defined code of the GRIB format */
+  GRIB_USERDEF = 129,
+};
+
 void
 var_scale(int datatype, double *mscale, double *mrscale);