errno 63 (ENAMETOOLONG): meaning and diagnosis

Status / error code:		Category:

Constant name:
Source:		Operating System:
Description: A pathname or one of its components exceeds a length limit accepted by the filesystem or interface.

Could be also:
Constant	Type	OS
ERROR_PRINT_CANCELLED	Win32 error	Windows
STATUS_WAIT_63	NTSTATUS	Windows
ENOSR	errno	Linux
ENOSR	errno	Solaris
NO_MORE_SYSTEM_PTES	BugCheck Code	Windows

Previous	Next
ELOOP	EHOSTDOWN

ENAMETOOLONG

Find the limit that was exceeded

ENAMETOOLONG does not necessarily mean that the visible filename alone is long. The limit can apply to a single path component, the complete pathname supplied to an interface, or a generated name after a prefix, staging directory, suffix, and separator are added.

Do not truncate names without preserving uniqueness and without considering Unicode normalization. A collision-safe naming scheme should reserve space for the generated suffix before writing output, and code that constructs paths must check the final length rather than the source identifier in isolation.

Diagnostic data

Log the full byte length of the submitted path and the length of every component after all substitutions.
Record the filesystem and mount point, because component limits can differ between filesystems.
Separate an overlong path from ELOOP; both occur during lookup, but only ELOOP involves symbolic-link traversal.

References

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