SPI_cursor_find — find an existing cursor by name
Portal SPI_cursor_find(const char * name)
   SPI_cursor_find finds an existing portal by
   name.  This is primarily useful to resolve a cursor name returned
   as text by some other function.
  
const char * namename of the portal
   pointer to the portal with the specified name, or
   NULL if none was found
  
   Beware that this function can return a Portal object
   that does not have cursor-like properties; for example it might not
   return tuples.  If you simply pass the Portal pointer
   to other SPI functions, they can defend themselves against such
   cases, but caution is appropriate when directly inspecting
   the Portal.