Assert that the argument to ‘-p’ isn’t emptyv1.0.2

1 files changed, 7 insertions, 0 deletions

diff --git a/main.l b/main.l
index 3ccae4a..2d26cd0 100644
--- a/main.l
+++ b/main.l
@@ -12,6 +12,8 @@ const char empty_field[] = "argument to the -p option contains an empty field";
 const char invalid_char[] = "argument to the -p option must be a "
                             "comma-seperated list of positive integers";
 const char final_comma[] = "argument to the -p option contains trailing comma";
+const char empty_string[] = "argument to the -p option cannot be "
+                            "the empty string";
 
 const char *argv0;
 unsigned pos;
@@ -102,6 +104,11 @@ append_positions(char *raw)
 		usage();
 	}
 
+	if (*raw == '\0') {
+		warnx(empty_string);
+		usage();
+	}
+
 	for (s = raw, positions.len++; *s; s++) {
 		switch (*s) {
 		case ',':