diff --git a/general/g.region/printwindow.c b/general/g.region/printwindow.c
index 865e33b5ae1..25d162c0402 100644
--- a/general/g.region/printwindow.c
+++ b/general/g.region/printwindow.c
@@ -622,7 +622,10 @@ void print_window(struct Cell_head *window, int print_flag, int flat_flag,
         double convergence;
 
         if (G_projection() == PROJECTION_XY)
-            convergence = NAN;
+            // GCC 5.4.0 says 0./0. is -nan
+            // Clang 3.8.0 says 0./0. is nan
+            // I stick to -nan in msvc too. But this has to rechecked.
+            sscanf("-nan", "%lf", &convergence);
         else if (G_projection() == PROJECTION_LL)
             convergence = 0.0;
         else {
diff --git a/lib/btree2/kdtree.c b/lib/btree2/kdtree.c
index ec0d19e0abc..4c3090a9664 100644
--- a/lib/btree2/kdtree.c
+++ b/lib/btree2/kdtree.c
@@ -531,7 +531,7 @@ int kdtree_knn(struct kdtree *t, double *c, int *uid, double *d, int k,
     if (skip)
         sn.uid = *skip;
 
-    maxdist = INFINITY;
+    sscanf("inf", "%lf", &maxdist);
     found = 0;
 
     /* go down */
diff --git a/lib/vector/Vlib/box.c b/lib/vector/Vlib/box.c
index 5ab5ef74e2d..48028852abd 100644
--- a/lib/vector/Vlib/box.c
+++ b/lib/vector/Vlib/box.c
@@ -247,7 +247,9 @@ int Vect_get_line_box(struct Map_info *Map, int line, struct bound_box *Box)
 
     Line = Plus->Line[line];
     if (Line == NULL) { /* dead */
-        Box->N = Box->S = Box->E = Box->W = Box->T = Box->B = NAN;
+        double nan_val;
+        sscanf("-nan", "%lf", &nan_val);
+        Box->N = Box->S = Box->E = Box->W = Box->T = Box->B = nan_val;
         return 0;
     }
 
@@ -311,7 +313,9 @@ int Vect_get_area_box(struct Map_info *Map, int area, struct bound_box *Box)
     Area = Plus->Area[area];
 
     if (Area == NULL) { /* dead */
-        Box->N = Box->S = Box->E = Box->W = Box->T = Box->B = NAN;
+        double nan_val;
+        sscanf("-nan", "%lf", &nan_val);
+        Box->N = Box->S = Box->E = Box->W = Box->T = Box->B = nan_val;
         return 0;
     }
 
@@ -357,7 +361,9 @@ int Vect_get_isle_box(struct Map_info *Map, int isle, struct bound_box *Box)
     Isle = Plus->Isle[isle];
 
     if (Isle == NULL) { /* dead */
-        Box->N = Box->S = Box->E = Box->W = Box->T = Box->B = NAN;
+        double nan_val;
+        sscanf("-nan", "%lf", &nan_val);
+        Box->N = Box->S = Box->E = Box->W = Box->T = Box->B = nan_val;
         return 0;
     }
 
diff --git a/raster/r.in.bin/main.c b/raster/r.in.bin/main.c
index 9bd677eb274..45881f361cc 100644
--- a/raster/r.in.bin/main.c
+++ b/raster/r.in.bin/main.c
@@ -255,7 +255,8 @@ int main(int argc, char *argv[])
     const char *outpre;
     char output[GNAME_MAX];
     const char *title;
-    double null_val = NAN;
+    double null_val;
+    sscanf("-nan", "%lf", &null_val);
     int is_fp;
     int is_signed;
     int bytes, hbytes;
diff --git a/raster/r.in.lidar/info.c b/raster/r.in.lidar/info.c
index 0eb11819e3c..edab13c0829 100644
--- a/raster/r.in.lidar/info.c
+++ b/raster/r.in.lidar/info.c
@@ -97,7 +97,9 @@ int scan_bounds(LASReaderH LAS_reader, int shell_style, int extents, int update,
     first = TRUE;
 
     /* init to nan in case no points are found */
-    min_x = max_x = min_y = max_y = min_z = max_z = NAN;
+    double nan_val;
+    sscanf("-nan", "%lf", &nan_val);
+    min_x = max_x = min_y = max_y = min_z = max_z = nan_val;
 
     G_verbose_message(_("Scanning data ..."));
 
diff --git a/raster/r.li/r.li.padrange/padrange.c b/raster/r.li/r.li.padrange/padrange.c
index dc383376b64..de55bb9c1dc 100644
--- a/raster/r.li/r.li.padrange/padrange.c
+++ b/raster/r.li/r.li.padrange/padrange.c
@@ -317,8 +317,8 @@ int calculate(int fd, struct area_entry *ad, double *result)
                       (((NS_DIST1 + NS_DIST2) / 2) / hd.rows);
 
         /* get min and max patch size */
-        min = INFINITY;
-        max = -INFINITY;
+        sscanf("inf", "%lf", &min);  /* inf */
+        sscanf("-inf", "%lf", &max); /* -inf */
         for (old_pid = 1; old_pid <= pid; old_pid++) {
             if (pst[old_pid].count > 0) {
                 area_p = cell_size_m * pst[old_pid].count / 10000;
@@ -561,8 +561,8 @@ int calculateD(int fd, struct area_entry *ad, double *result)
                       (((NS_DIST1 + NS_DIST2) / 2) / hd.rows);
 
         /* get min and max patch size */
-        min = INFINITY;
-        max = -INFINITY;
+        sscanf("inf", "%lf", &min);  /* inf */
+        sscanf("-inf", "%lf", &max); /* -inf */
         for (old_pid = 1; old_pid <= pid; old_pid++) {
             if (pst[old_pid].count > 0) {
                 area_p = cell_size_m * pst[old_pid].count / 10000;
@@ -805,8 +805,8 @@ int calculateF(int fd, struct area_entry *ad, double *result)
                       (((NS_DIST1 + NS_DIST2) / 2) / hd.rows);
 
         /* get min and max patch size */
-        min = INFINITY;
-        max = -INFINITY;
+        sscanf("inf", "%lf", &min);  /* inf */
+        sscanf("-inf", "%lf", &max); /* -inf */
         for (old_pid = 1; old_pid <= pid; old_pid++) {
             if (pst[old_pid].count > 0) {
                 area_p = cell_size_m * pst[old_pid].count / 10000;
diff --git a/raster/r.out.gdal/main.c b/raster/r.out.gdal/main.c
index dcb0c9d4e5a..9d946cf8791 100644
--- a/raster/r.out.gdal/main.c
+++ b/raster/r.out.gdal/main.c
@@ -998,6 +998,8 @@ int nodataval_check(double nodataval, GDALDataType datatype)
 
 double set_default_nodata_value(GDALDataType datatype, double min, double max)
 {
+    double nan_val;
+    sscanf("-nan", "%lf", &nan_val);
     switch (datatype) {
     case GDT_Byte:
         if (max < TYPE_BYTE_MAX)
@@ -1043,11 +1045,11 @@ double set_default_nodata_value(GDALDataType datatype, double min, double max)
 
     case GDT_Float32:
     case GDT_CFloat32:
-        return NAN;
+        return nan_val;
 
     case GDT_Float64:
     case GDT_CFloat64:
-        return NAN;
+        return nan_val;
 
     default:
         return 0;
diff --git a/raster/r.series.accumulate/main.c b/raster/r.series.accumulate/main.c
index 2c526c30257..b17ec50725f 100644
--- a/raster/r.series.accumulate/main.c
+++ b/raster/r.series.accumulate/main.c
@@ -171,8 +171,8 @@ int main(int argc, char *argv[])
     if (G_parser(argc, argv))
         exit(EXIT_FAILURE);
 
-    lo = -INFINITY;
-    hi = INFINITY;
+    sscanf("-inf", "%lf", &lo);
+    sscanf("inf", "%lf", &hi);
     method = METHOD_GDD;
     if (G_strncasecmp(parm.method->answer, "gdd", 3) == 0)
         method = METHOD_GDD;
diff --git a/raster/r.series/main.c b/raster/r.series/main.c
index 387f164b96b..e05b0e716d9 100644
--- a/raster/r.series/main.c
+++ b/raster/r.series/main.c
@@ -227,8 +227,8 @@ int main(int argc, char *argv[])
     threaded = nprocs > 1;
 #endif
 
-    lo = -INFINITY;
-    hi = INFINITY;
+    sscanf("-inf", "%lf", &lo);
+    sscanf("inf", "%lf", &hi);
     if (parm.range->answer) {
         lo = atof(parm.range->answers[0]);
         hi = atof(parm.range->answers[1]);
diff --git a/raster/r.univar/r3.univar_main.c b/raster/r.univar/r3.univar_main.c
index f14d50746a7..4eff2d386cb 100644
--- a/raster/r.univar/r3.univar_main.c
+++ b/raster/r.univar/r3.univar_main.c
@@ -198,8 +198,8 @@ int main(int argc, char *argv[])
     /* table field separator */
     zone_info.sep = G_option_to_separator(param.separator);
 
-    dmin = NAN;
-    dmax = NAN;
+    sscanf("-nan", "%lf", &dmin); /* set to nan as default */
+    sscanf("-nan", "%lf", &dmax); /* set to nan as default */
     zone_info.min = 0;
     zone_info.max = 0;
     zone_info.n_zones = 0;
diff --git a/raster/r.univar/stats.c b/raster/r.univar/stats.c
index e868d0ce2b0..e6abbcb5781 100644
--- a/raster/r.univar/stats.c
+++ b/raster/r.univar/stats.c
@@ -22,6 +22,8 @@ univar_stat *create_univar_stat_struct(int map_type, int n_perc)
     univar_stat *stats;
     int i;
     int n_zones = zone_info.n_zones;
+    double nan_val;
+    sscanf("-nan", "%lf", &nan_val);
 
     if (n_zones == 0)
         n_zones = 1;
@@ -31,8 +33,8 @@ univar_stat *create_univar_stat_struct(int map_type, int n_perc)
     for (i = 0; i < n_zones; i++) {
         stats[i].sum = 0.0;
         stats[i].sumsq = 0.0;
-        stats[i].min = NAN;
-        stats[i].max = NAN;
+        stats[i].min = nan_val; /* set to nan as default */
+        stats[i].max = nan_val; /* set to nan as default */
         stats[i].n_perc = n_perc;
         if (n_perc > 0)
             stats[i].perc = (double *)G_malloc(n_perc * sizeof(double));
@@ -108,6 +110,8 @@ int print_stats(univar_stat *stats, enum OutputFormat format)
     }
 
     int z, n_zones = zone_info.n_zones;
+    double nan_val;
+    sscanf("-nan", "%lf", &nan_val);
 
     if (n_zones == 0)
         n_zones = 1;
@@ -136,8 +140,9 @@ int print_stats(univar_stat *stats, enum OutputFormat format)
         stdev = sqrt(variance);
         var_coef = (stdev / mean) * 100.; /* perhaps stdev/fabs(mean) ? */
 
-        if (stats[z].n == 0)
-            stats[z].sum = stats[z].sum_abs = NAN;
+        if (stats[z].n == 0) {
+            stats[z].sum = stats[z].sum_abs = nan_val;
+        }
         snprintf(sum_str, sizeof(sum_str), "%.15g", stats[z].sum);
         G_trim_decimal(sum_str);
 
@@ -272,9 +277,9 @@ int print_stats(univar_stat *stats, enum OutputFormat format)
             quartile_perc = (double *)G_calloc(stats[z].n_perc, sizeof(double));
 
             if (stats[z].n == 0) {
-                quartile_25 = median = quartile_75 = NAN;
+                quartile_25 = median = quartile_75 = nan_val;
                 for (i = 0; i < stats[z].n_perc; i++)
-                    quartile_perc[i] = NAN;
+                    quartile_perc[i] = nan_val;
             }
             else {
                 for (i = 0; i < stats[z].n_perc; i++) {
@@ -510,6 +515,8 @@ int print_stats_table(univar_stat *stats)
 {
     unsigned int i;
     int z, n_zones = zone_info.n_zones;
+    double nan_val;
+    sscanf("-nan", "%lf", &nan_val);
 
     if (n_zones == 0)
         n_zones = 1;
@@ -584,7 +591,7 @@ int print_stats_table(univar_stat *stats)
         var_coef = (stdev / mean) * 100.; /* perhaps stdev/fabs(mean) ? */
 
         if (stats[z].n == 0)
-            stats[z].sum = stats[z].sum_abs = NAN;
+            stats[z].sum = stats[z].sum_abs = nan_val;
 
         if (zone_info.n_zones) {
             int z_cat = z + zone_info.min;
@@ -632,9 +639,9 @@ int print_stats_table(univar_stat *stats)
             quartile_perc = (double *)G_calloc(stats[z].n_perc, sizeof(double));
 
             if (stats[z].n == 0) {
-                quartile_25 = median = quartile_75 = NAN;
+                quartile_25 = median = quartile_75 = nan_val;
                 for (i = 0; i < stats[z].n_perc; i++)
-                    quartile_perc[i] = NAN;
+                    quartile_perc[i] = nan_val;
             }
             else {
                 for (i = 0; i < stats[z].n_perc; i++) {
diff --git a/raster3d/r3.in.lidar/info.c b/raster3d/r3.in.lidar/info.c
index bf953f1d8b8..da4fd86fc4b 100644
--- a/raster3d/r3.in.lidar/info.c
+++ b/raster3d/r3.in.lidar/info.c
@@ -101,7 +101,9 @@ int scan_bounds(LASReaderH LAS_reader, int shell_style, int extents, int update,
     first = TRUE;
 
     /* init to nan in case no points are found */
-    min_x = max_x = min_y = max_y = min_z = max_z = NAN;
+    double nan_val;
+    sscanf("-nan", "%lf", &nan_val);
+    min_x = max_x = min_y = max_y = min_z = max_z = nan_val;
 
     G_verbose_message(_("Scanning data ..."));
 
diff --git a/vector/v.cluster/main.c b/vector/v.cluster/main.c
index 49c7535beca..fece56d4e66 100644
--- a/vector/v.cluster/main.c
+++ b/vector/v.cluster/main.c
@@ -256,7 +256,7 @@ int main(int argc, char *argv[])
             c[2] = 0.0;
             n = 0;
             sum = sumsq = 0;
-            min = INFINITY;
+            sscanf("inf", "%lf", &min);
             max = 0;
             kd = G_malloc(minpnts * sizeof(double));
             ki = G_malloc(minpnts * sizeof(int));
@@ -462,7 +462,7 @@ int main(int argc, char *argv[])
             c[2] = 0.0;
             n = 0;
             sum = sumsq = 0;
-            min = INFINITY;
+            sscanf("inf", "%lf", &min);
             max = 0;
             kd = G_malloc(minpnts * sizeof(double));
             ki = G_malloc(minpnts * sizeof(int));
diff --git a/vector/v.distance/distance.c b/vector/v.distance/distance.c
index 74c6d88a40d..569ee5812ea 100644
--- a/vector/v.distance/distance.c
+++ b/vector/v.distance/distance.c
@@ -11,7 +11,9 @@ int get_line_box(const struct line_pnts *Points, struct bound_box *box)
     int i;
 
     if (Points->n_points == 0) {
-        box->E = box->W = box->N = box->S = box->T = box->B = NAN;
+        double nan_val;
+        sscanf("-nan", "%lf", &nan_val);
+        box->E = box->W = box->N = box->S = box->T = box->B = nan_val;
         return 0;
     }
 
diff --git a/vector/v.voronoi/skeleton.c b/vector/v.voronoi/skeleton.c
index 9e052b76d0e..226e55d5071 100644
--- a/vector/v.voronoi/skeleton.c
+++ b/vector/v.voronoi/skeleton.c
@@ -533,7 +533,7 @@ int tie_up(void)
                                  IPoints[i]);
         }
 
-        distmin = INFINITY;
+        sscanf("inf", "%lf", &distmin);
         xmin = x;
         ymin = y;