What does errno 72 (ELOCKUNMAPPED) in Solaris mean?

ELOCKUNMAPPED

Obsolete robust-lock compatibility code

ELOCKUNMAPPED is Solaris errno 72 (locked lock was unmapped). Solaris keeps this obsolete robust-lock value for compatibility; modern recovery uses EOWNERDEAD.

Because this is an obsolete compatibility value, first identify the interface that still returns it. Modern robust-mutex handling should normally proceed through owner-death recovery semantics rather than application-specific handling of this legacy errno.

What to check

• If old binaries report it, examine robust mutex lifecycle and mappings that disappeared while a lock was held.
• For new code, handle EOWNERDEAD and ENOTRECOVERABLE explicitly.
• Do not build new logic that depends on this errno being produced by modern interfaces.

References

• Oracle Solaris intro(2): error numbers
• illumos errno.h definitions
• POSIX errno.h