In LDD3, Chapter 6, Section "Restricting Access to a Single User at a Time", the example code returns -EBUSY when the chardev is in use by another user. However, I "man 3p open" and "man 2 open", finding that ERRORS section of either manual didn't mention about EBUSY. I would like to ask if it's legal for open() to return -EBUSY. Zheng Lv -- To unsubscribe from this list: send the line "unsubscribe linux-newbie" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.linux-learn.org/faqs