fconvert
extern char *fconvert(double, int, int *, int *, char *);
ptr = fconvert(number, ndigits, decpt, sign, buf);
ptr = fconvert(number, ndigits, decpt, sign, buf);
FPCONV(fconvert, dval, min(prec, MAXFCVT),
ptr = fconvert(number, ndigits, decpt, sign, buf);
ptr = fconvert(number, ndigits, decpt, sign, buf);