string: Set result pointer to NULL on errors.

...and be strict in what you return.

diff --git a/string.c b/string.c
index b16109c..0a32c0f 100644 (file)
--- a/string.c
+++ b/string.c
@@ -762,6 +762,7 @@ err:
        while (num_words > 0)
                free(argv[--num_words]);
        free(argv);
+       *result = NULL;
        return ret;
 }