H_NSAVE_FP
history(hist, &he, H_NSAVE_FP, (size_t)0, HistFP);
#define HIST_NSAVE_FP(el, n, fp) HIST_FUN(el, H_NSAVE_FP, n, fp)
case H_NSAVE_FP:
if (history(h, &ev, H_NSAVE_FP, (size_t)n, fp) == -1) {