Font Class. Font instances belong to the workbook (see Fn'LibXL'GetFontCount and Fn'LibXL'GetFont in the Book Class functions). Each Font instance may be shared by any number of Format instances (which is how they get associated with cells). So the standard procedure for defining fonts involves using the Book class function Fn’LibXL’AddFont to create a font instance and add it to the book, then using the Font class function LibXL’FontSetAttributes to assign attributes to it. Or, you can combine these two steps using the Fn’LibXL’AddFont’SetAttributes function.

Format Class. Each cell (individually, or in rows or columns) is associated with a single instance of the Format class, which determines the non-data attributes for the cell (alignment, color, font, numeric format or mask, etc.). As with Fonts, the Format instances belong to the Book class, so the standard procedure for defining a Format would be to use the Book class function Fn’LibXL’AddFormat, and then pass the returned Format instance handle to the Format class procedure LibXL’FormatSetAttributes to assign the attributes of the format. Or, you can combine those two steps with the Fn’LibXL’AddFormat’SetAttributes function.

Also note the overuse of the word “format” to refer both to the Format class, as well as to number formats, either the standard built-in ones identified by NUMFMT_xxx identifiers, or custom ones you define via a mask. (We try to minimize the confusion by using the abbreviation “Fmt” when referring to the number formats, reserving “Format” to refer to the Format class.)

Custom numeric formats are also owned by the Book, and have to be created and added to the book before they can be associated with an instance of the Format class. Again you can perform those steps separately, starting with the Book class function Fn'LibXL'AddCustomNumFmt and Format class function Fn’LibXL’FormatSetNumFmt, or use the combined function Fn’LibXL’Format’AddSetCustomNumFmt.

Misc Routines (not associated with a class):