prin1-to-string

prin1-to-string is a built-in function in `C source code'.

(prin1-to-string OBJECT &optional NOESCAPE)

Return a string containing the printed representation of OBJECT.
OBJECT can be any Lisp object. This function outputs quoting characters
when necessary to make output that `read' can handle, whenever possible,
unless the optional second argument NOESCAPE is non-nil. For complex objects,
the behavior is controlled by `print-level' and `print-length', which see.

OBJECT is any of the Lisp data types: a number, a string, a symbol,
a list, a buffer, a window, a frame, etc.

A printed representation of an object is text which describes that object.