Inno Setup [Registry] - Using function return value

Question

Is there anyway to have the return value of a function for the ValueData (or similar property). Tried the following:

Root: HKLM; Subkey: "SYSTEM\CurrentControlSet\Control\Session Manager\Environment"; \
   ValueType: string; ValueName: "Hostname"; ValueData: GetComputerNameString(); \
   Flags: preservestringtype;

But this simply adds the string GetComputerNameString() to the registry item.

Answer 1

Use a scripted constant, with syntax {code:FunctionName}. Though the scripted constant function must take a string parameter (even if the actual implementation does not need any parameter). So the GetComputerNameString is not compatible. You have to create a proxy function.

[Registry]
Root: HKLM; \
    Subkey: "SYSTEM\CurrentControlSet\Control\Session Manager\Environment"; \
    ValueType: string; ValueName: "Hostname"; ValueData: {code:GetComputerName}; \
    Flags: preservestringtype;

[Code]

function GetComputerName(Param: string): string;
begin
  Result := GetComputerNameString;
end; 

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For a more complex example, see Inno Setup [Code] section variable to [Registry].