shared directory and multiple directories incompatibility

[KnightKu]

Hi guys,
Why the shared directory and multiple directories are incompatibility?

/* check for shared directory and multiple directories incompatibility */
if (path_count > 1 && unique_dir_per_task != 1) {
FAIL("shared directory mode is not compatible with multiple directory paths");
}

[glennklockwood]

My guess is that it becomes non-trivial to decide how to spread files out over multiple shared directories. If you can provide a patch that provides that logic, I'm sure it would be welcome for review.