




 
The function 
registry-key-exists-p
 checks whether the registry key named 
subkey
 can be opened under the parent key 
root
 with the supplied 
access
 permissions.
subkey
 and 
root
 are interpreted as described for create-registry-key. The default value of 
root
 is 
:user
.
If 
access
 is 
:read
, then it opens the key with 
KEY_READ
 permissions.  If 
access
 is 
:write
, then it opens the key with 
KEY_WRITE
 permissions.  If 
access
 is an integer, then the value 
access
 specifies the desired Win32 access rights.  If 
access
 is omitted and 
root
 is 
:user
, then 
registry-key-exists-p
  uses 
KEY_ALL_ACCESS
. Otherwise it uses 
KEY_READ
.
registry-key-exists-p
 closes the key before returning, but the return value is 
t
 if the key could actually be opened and 
nil
 otherwise.
LispWorks User Guide and Reference Manual - 21 Dec 2011