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Write Key And Return Previous Value (LCC.kvdb.dict.put)

Signature​

old_value, err = LCC.kvdb.dict.put(name, key, value, timeout?)

Parameters​

  • name
    String. Dictionary name (non-empty, max 256 bytes).
  • key
    String. Key (must be valid UTF-8 and non-empty).
  • value
    String. New value (must be valid UTF-8).
  • timeout
    Number, optional. Request timeout in seconds, default 60.

Returns​

  • old_value
    String or nil. Previous value when the key existed; nil for new keys.
  • err
    String or nil. For new keys this is 'not found'; otherwise contains the error message.

Notes​

Writes a key and atomically returns its previous value—useful for "set-and-get-old" operations.
When the request fails, the function returns false followed by the error message.

Example​

local old, err = LCC.kvdb.dict.put("settings", "retry", "3")
if old == false then
    error(err)
end