current-fill-columncurrent-fill-column is a compiled Lisp function in `
fill.el'. (current-fill-column) Return the fill-column to use for this line. The fill-column to use for a buffer is stored in the variable `fill-column', but can be locally modified by the `right-margin' text property, which is subtracted from `fill-column'. The fill column to use for a line is the first column at which the column number equals or exceeds the local fill-column - right-margin difference.