saxon:format-number($value as xs:double, $picture as xs:string) as xs:string

This function (in the Saxon namespace) is available in Saxon-SA only.

This function is identical to the two-argument version of the format-number function in XSLT 2.0, but in the Saxon namespace. It uses the default behavior of the XSLT function when there is no xsl:decimal-format declaration in the stylesheet, which means that it is not possible to change the characters used as the decimal point, grouping separator, and so on.

For example, the call saxon:format-number(123.4567, '0000.00') produces the output 0123.46.

For full details, see the current draft of the XSLT 2.0 specification.