Hi,

Where I must put headed, like the following one?
Function RegDeleteKey(hKey: Longint; lpSubKey: String): Longint;
external 'advapi32' name 'RegDeleteKeyA';

Program key1;  //This program works.
Const
HKEY_LOCAL_MACHINE = $80000002;
Function RegDeleteKey(hKey: Longint; lpSubKey: String): Longint;
external
 'advapi32' name 'RegDeleteKeyA';
Var
 Val: LongInt;
Begin
 Val := RegDeleteKey(HKEY_LOCAL_MACHINE, 'Software\Luis Digital');
End.
============================================
Program Key2;  //This program does not work.
Uses windows;
Var
 Val: Long;
Begin
 Val := RegDeleteKeyW(HKEY_LOCAL_MACHINE, 'Software\Luis Digital');
End. // RegDeleteKeyW(HKEY,                LPCWSTR = ^Word);

There is an error in the declaration or I do not know to use the function?

Here you use "RegDeleteKeyA"

Begin Val := RegDeleteKeyW(HKEY_LOCAL_MACHINE, 'Software\Luis Digital'); End. // RegDeleteKeyW(HKEY, LPCWSTR = ^Word);

Here you use RegDeleteKeyW (which is for widestrings)

There is an error in the declaration or I do not know to use the function?

Try to use RegDeleteKeyA or only RegDeleteKey in the second example.

Marco van de Voort ( or )

Where I must put headed, like the following one? Function RegDeleteKey(hKey: Longint; lpSubKey: String): Longint; external 'advapi32' name 'RegDeleteKeyA';

Nowhere? It is simply in unit windows?

Marco van de Voort ( or )

Work.

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Thanks.