The setCallback purpose

# EventListener::setCallback

(PECL event >= 1.2.6-beta)

EventListener::setCallback — The setCallback purpose

### Description

public EventListener::setCallback( callable `$cb` , mixed `$arg` = `null` ): void

Adjust event connect listener's callback and optionally the callback argument.

### Parameters

`cb`

  The new callback for new connections. Ignored if `null`.

  Should match the following prototype:

  callback(
  EventListener `$listener` = `null` ,
  mixed `$fd` = `null` ,
  array `$address` = `null` ,
  mixed `$arg` = `null`
  ): void
  `listener`

    The EventListener object.

  `fd`

    The file descriptor or a resource associated with the listener.

  `address`

    Array of two elements: IP address and the server port.

  `arg`

    User custom data attached to the callback.

`arg`

  Custom user data attached to the callback. Ignored if `null`.

### Return Values

No value is returned.

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