[Unix; common]
1. Something passed between routines or programs that enables the
receiver to perform some operation; a capability ticket or opaque
identifier. Especially used of small data objects that contain data
encoded in a strange or intrinsically machine-dependent way. E.g., on
non-Unix OSes with a non-byte-stream model of files, the result of
ftell(3) may be a magic cookie rather than a byte offset; it can be
passed to fseek(3), but not operated on in any meaningful way. The
phrase it hands you a magic cookie means it returns a result whose
contents are not defined but which can be passed back to the same or
some other program later.
2. An in-band code for changing graphic rendition (e.g., inverse
video or underlining) or performing other control functions (see also
{cookie}). Some older terminals would leave a blank on the screen
corresponding to mode-change magic cookies; this was also called a
{glitch} (or occasionally a turd; compare {mouse droppings}). See
also {cookie}.
[glossary]
[Reference(s) to this entry by made by: {cookie}{glitch}{handle}{tumbler}]