ENODEV

ENODEV is a standard errno value used in Unix-like operating systems to indicate that a requested operation cannot be performed because no such device is available. In Linux, ENODEV is typically defined as 19 and is raised when a system call expects a device to be present or configured, but the kernel cannot provide one.

The error commonly occurs in device-related operations. For example, attempting to open a device file in /dev that has no corresponding driver loaded or that represents a non-existent hardware device can yield ENODEV. Mounting a filesystem type for which the kernel has no built-in support or without an appropriate module can also produce ENODEV. In general, ENODEV means the requested device either does not exist in the system's device tree or is not currently accessible due to missing drivers or hardware.

In application code, ENODEV is returned by system calls that fail, with -1 indicating failure and errno set to ENODEV. Programmers can inspect errno or use strerror to report the error in a human-readable form. ENODEV is distinct from ENOENT (no such file or directory) and ENXIO or ENOTTY, which have different meanings related to non-existent files, bad addresses, or inapplicable I/O controls.

Diagnosis and remediation typically involve confirming the hardware presence, ensuring the correct device node exists under /dev, loading the appropriate kernel driver or module (using modprobe or udev), and checking kernel logs (dmesg) for related messages. Verifying permissions and device major/minor numbers can also help resolve ENODEV.

See also: ENOENT, ENXIO, ENOTTY, errno.