Provided by: libfontconfig1-dev_2.12.6-0ubuntu2_amd64 

NAME
FcCharSetSubtract - Subtract charsets
SYNOPSIS
#include <fontconfig/fontconfig.h>
FcCharSet * FcCharSetSubtract (const FcCharSet *a, const FcCharSet *b);
DESCRIPTION
Returns a set including only those chars found in a but not b.
Fontconfig 2.12.6 05 April 2018 FcCharSetSubtract(3)