What does errno 38 (ENAMETOOLONG) mean?

Status / error code:		Category:

Constant name:
Source:		Operating System:
Description: A UCRT errno status indicating that a path or filename cannot be represented within the limit accepted by the called API.

Could be also:
Constant	Type	OS
ERROR_HANDLE_EOF	Win32 error	Windows
KERN_LOCK_SET_DESTROYED	Kern return	Mac
ippStsSymKernelExpected	Intel Ipp Status	Any
ENOSYS	errno	Linux
ENOTSOCK	errno	Mac
EL2NSYNC	errno	Solaris
CDFS_FILE_SYSTEM	BugCheck Code	Windows

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EL2NSYNC	ENOTEMPTY

ENAMETOOLONG

ENAMETOOLONG means the pathname supplied to the relevant C-runtime or portability-layer operation exceeds a limit that the operation can accept. It is not safe to diagnose it from the final filename alone: the complete path, its individual components, the filesystem, the API family, and the path syntax all matter.

Windows has several overlapping path rules. Legacy APIs can encounter MAX_PATH-related limits, while Unicode extended-length paths can use a different form and filesystem components may impose separate limits. A path that is acceptable to one API or filesystem can still fail in an older library, a shell-facing workflow, a relative-path call, or an archive extraction step.

What to capture

Log the complete path length, each component length, whether it is relative, drive-based, UNC, or extended-length, and which API accepted the input.
Do not truncate a path silently: truncation can redirect an operation to a different object or create collisions.
Check the target filesystem and deployment location, especially when a build, Git checkout, package extractor, or sync client adds nested directories.
Use the documented Unicode API and long-path model deliberately; adding a prefix changes parsing rules and is not a universal string substitution.

References

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