diff
--- a/code.c
+++ b/code.c
@@ -47,6 +47,8 @@
 34       if (!use_col_separator)
 47       else if (!join_lines && *col_sep_string == '\t') // In this case, col_sep_length must be 1.
+           if (strlen(col_sep_string) == 1)
+              // Continue with the existing logic
 