diff
--- a/code.c
+++ b/code.c
@@ -1,6 +1,7 @@
 1 static void
 2 init_parameters (int number_of_files)
-20   if (number_of_files == 0)
+20   bool single_tab = false;
+21   if (number_of_files == 0)
 21     parallel_files = false;
 23   if (parallel_files)
 24     columns = number_of_files;
@@ -47,7 +48,9 @@
 34       if (!use_col_separator)
 47       else if (!join_lines && *col_sep_string == '\t') // In this case, col_sep_length must be 1.
-           if (col_sep_string[1] == '\0')
+           single_tab = true;
+           if (single_tab)
+              // Continue with the existing logic
 