create-fontset-from-fontset-spec is a compiled Lisp function in `fontset.el'.

(create-fontset-from-fontset-spec FONTSET-SPEC &optional STYLE-VARIANT NOERROR)

Create a fontset from fontset specification string FONTSET-SPEC.
FONTSET-SPEC is a string of the format:
Any number of SPACE, TAB, and NEWLINE can be put before and after commas.

When a frame uses the fontset as the `font' parameter, the frame's
default font name is derived from FONTSET-NAME by substituting
"iso8859-1" for the tail part "fontset-XXX". But, if SCRIPT-NAMEn
is "ascii", use the corresponding FONT-NAMEn as the default font

Optional 2nd and 3rd arguments exist just for backward compatibility,
and are ignored.

It returns a name of the created fontset.

For backward compatibility, SCRIPT-NAME may be a charset name, in
which case, the corresponding script is decided by the variable
`charset-script-alist' (which see).