--- /dev/null
+/* $OpenBSD: floatio.h,v 1.4 2008/09/07 20:36:08 martynas Exp $ */
+
+/*
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (C) 1990, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Chris Torek.
+ */
+
+/*
+ * Floating point scanf/printf (input/output) definitions.
+ */
+
+/* 11-bit exponent (VAX G floating point) is 308 decimal digits */
+#define MAXEXP 308
+/* 128 bit fraction takes up 39 decimal digits; max reasonable precision */
+#define MAXFRACT 39
+
+/*
+ * MAXEXPDIG is the maximum number of decimal digits needed to store a
+ * floating point exponent in the largest supported format. It should
+ * be ceil(log10(LDBL_MAX_10_EXP)) or, if hexadecimal floating point
+ * conversions are supported, ceil(log10(LDBL_MAX_EXP)). But since it
+ * is presently never greater than 5 in practice, we fudge it.
+ */
+#define MAXEXPDIG 6
+#if LDBL_MAX_EXP > 999999
+#error "floating point buffers too small"
+#endif
+
+char *__hdtoa(double, const char *, int, int *, int *, char **)
+ __attribute__((visibility("hidden")));
+
+char *__hldtoa(long double, const char *, int, int *, int *, char **)
+ __attribute__((visibility("hidden")));
+
+char *__ldtoa(long double *, int, int, int *, int *, char **)
+ __attribute__((visibility("hidden")));