Evaluates code with a hash-table locked against modification by other threads.
with-hash-table-locked hash-table &body body
A hash table.
The results of evaluating body.
with-hash-table-locked evaluates body with the hash table hash-table locked against modification by other threads. The current thread can modify hash-table.
with-hash-table-locked is useful not only for multiple accesses to the same table, but also when an access to the table must be consistent with some other operation, avoiding the need to make a separate lock,
LispWorks User Guide and Reference Manual - 20 Sep 2017