LinceCAD vl-string-position
(vl-string-position code string [start [from-end]])
Position (from 0) of the character with that code, or nil. With a non-nil fourth argument, finds the last occurrence.
(vl-string-position (ascii "\\") "C:\\dwg\\a.dwg" nil T) ; 6
(vl-string-position code string [start [from-end]])
Position (from 0) of the character with that code, or nil. With a non-nil fourth argument, finds the last occurrence.
(vl-string-position (ascii "\\") "C:\\dwg\\a.dwg" nil T) ; 6