Visual LISP, AutoLISP and General Customization

[#1]

I want to create a registry key using lisp but only if it dost already exist I know how to use the IF else function and how to create a registry key using lisp but not sure on how to check for the existence of a registry key with in a lisp program?

[#2]

vl-registry-read 

vl-registry-write

vl-registry-delete

or

GETENV and SETENV me thinks

HTH

[#3]

I think vl-registry-write will only make the key if it doesn't exist. Or, rather I should say, you will not lose any values already in that key by using vl-registry-write to try to create it.

So, why check first? (Unless you mean a registry "VALUE" or "DATA" and not "KEY")

Example:

Command: (vl-registry-read "HKEY_CURRENT_USER\\TestA")
nil

Key does not exist

Command: (vl-registry-write "HKEY_CURRENT_USER\\TestA")
T

Now it does but has no values

Command: (vl-registry-read "HKEY_CURRENT_USER\\TestA")
nil

read fails because it looks for a value

Command: (vl-registry-write "HKEY_CURRENT_USER\\TestA" "" "default-value")
"default-value"
I add a value

Command: (vl-registry-read "HKEY_CURRENT_USER\\TestA")
"default-value"

It reads a value

Command: (vl-registry-write "HKEY_CURRENT_USER\\TestA")
T

I re-write the key

Command: (vl-registry-read "HKEY_CURRENT_USER\\TestA")
"default-value"

value is still there

fugetaboutit