SET(PERMANENT)

  Sets a buffer to permanent, so it cannot be deleted.  This is useful if
  you create buffers for procedures to use in manipulating text or storing
  data.  By default, buffers are not permanent.

  Syntax

     SET (PERMANENT, buffer)

  Example

     SET (PERMANENT, paste_buffer);

  Sets the paste buffer to permanent, so it cannot be deleted.  Once you set
  a buffer to permanent, it cannot be reset so that it can be deleted.

  Related topics

     SET(NO_WRITE)   SET(OUTPUT_FILE)   SET(SYSTEM)