diff --git a/build-support/factor.sh b/build-support/factor.sh
index 3ece72306a..ba5815cfc1 100755
--- a/build-support/factor.sh
+++ b/build-support/factor.sh
@@ -205,7 +205,7 @@ find_architecture() {
 
 write_test_program() {
     echo "#include <stdio.h>" > $C_WORD.c
-    echo "int main(){printf(\"%ld\", 8*sizeof(void*)); return 0; }" >> $C_WORD.c
+    echo "int main(){printf(\"%ld\", (long)(8*sizeof(void*))); return 0; }" >> $C_WORD.c
 }
 
 c_find_word_size() {
diff --git a/vm/debug.c b/vm/debug.c
index 6f7e883785..a9afd2c3c0 100755
--- a/vm/debug.c
+++ b/vm/debug.c
@@ -414,7 +414,7 @@ void factorbug(void)
 		if(strcmp(cmd,"d") == 0)
 		{
 			CELL addr = read_cell_hex();
-			scanf(" ");
+			if(scanf(" ") < 0) break;
 			CELL count = read_cell_hex();
 			dump_memory(addr,addr+count);
 		}
diff --git a/vm/utilities.c b/vm/utilities.c
index d97b540884..ac52772b4e 100755
--- a/vm/utilities.c
+++ b/vm/utilities.c
@@ -50,6 +50,6 @@ void print_fixnum(F_FIXNUM x)
 CELL read_cell_hex(void)
 {
 	CELL cell;
-	scanf(CELL_HEX_FORMAT,&cell);
+	if(scanf(CELL_HEX_FORMAT,&cell) < 0) exit(1);
 	return cell;
 };