FcAtomicCreate - create an FcAtomic object
#include <fontconfig/fontconfig.h>
FcAtomic * FcAtomicCreate (const FcChar8 *file);
Creates a data structure containing data needed to control access to
  file. Writing is done to a separate file. Once that file is complete,
  the original configuration file is atomically replaced so that reading process
  always see a consistent and complete file without the need to lock for
  reading.