set TextureID = NULL after deleting the array
diff --git a/progs/tests/manytex.c b/progs/tests/manytex.c
index 28f7d3b..900e583 100644
--- a/progs/tests/manytex.c
+++ b/progs/tests/manytex.c
@@ -133,6 +133,7 @@
 {
    glDeleteTextures(NumTextures, TextureID);
    free(TextureID);
+   TextureID = NULL;
 }