diff --git a/src/dg_olc.c b/src/dg_olc.c
index ac28e01..1a4affa 100644
--- a/src/dg_olc.c
+++ b/src/dg_olc.c
@@ -1148,7 +1148,7 @@ int format_script(struct descriptor_data *d)
 
     *line = '\0';
     for (nlen = 0, i = 0;i<indent;i++) {
-      strncat(line, "  ", sizeof(line)-1);
+      strncat(line, "  ", sizeof(line) - strlen(line) - 1);
       nlen += 2;
     }
 
diff --git a/src/genzon.c b/src/genzon.c
index a604da4..bf672ce 100644
--- a/src/genzon.c
+++ b/src/genzon.c
@@ -268,7 +268,7 @@ void create_world_index(int znum, const char *type)
   while (get_line(oldfile, buf)) {
     if (*buf == '$') {
       /* The following used to add a blank line, thanks to Brian Taylor for the fix. */
-      fprintf(newfile, "%s", (!found ? strncat(buf1, "\n$\n", sizeof(buf1)-1) : "$\n"));
+      fprintf(newfile, "%s", (!found ? strncat(buf1, "\n$\n", sizeof(buf1) - strlen(buf1) - 1) : "$\n"));
       break;
     } else if (!found) {
       sscanf(buf, "%d", &num);