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	1	.\" Copyright (c) 1991, 1993
	2	.\" The Regents of the University of California. All rights reserved.
	3	.\"
	4	.\" This code is derived from software contributed to Berkeley by
	5	.\" the American National Standards Committee X3, on Information
	6	.\" Processing Systems.
	7	.\"
	8	.\" Redistribution and use in source and binary forms, with or without
	9	.\" modification, are permitted provided that the following conditions
	10	.\" are met:
	11	.\" 1. Redistributions of source code must retain the above copyright
	12	.\" notice, this list of conditions and the following disclaimer.
	13	.\" 2. Redistributions in binary form must reproduce the above copyright
	14	.\" notice, this list of conditions and the following disclaimer in the
	15	.\" documentation and/or other materials provided with the distribution.
	16	.\" 4. Neither the name of the University nor the names of its contributors
	17	.\" may be used to endorse or promote products derived from this software
	18	.\" without specific prior written permission.
	19	.\"
	20	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	21	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	22	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	23	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	24	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	25	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	26	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	27	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	28	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	29	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	30	.\" SUCH DAMAGE.
	31	.\"
	32	.\" @(#)atof.3 8.1 (Berkeley) 6/4/93
	33	.\" $FreeBSD: src/lib/libc/stdlib/atof.3,v 1.17 2007/01/09 00:28:09 imp Exp $
	34	.\"
	35	.Dd June 4, 1993
	36	.Dt ATOF 3
	37	.Os
	38	.Sh NAME
	39	.Nm atof ,
	40	.Nm atof_l
	41	.Nd convert
	42	.Tn ASCII
	43	string to double
	44	.Sh LIBRARY
	45	.Lb libc
	46	.Sh SYNOPSIS
	47	.In stdlib.h
	48	.Ft double
	49	.Fn atof "const char *str"
	50	.In xlocale.h
	51	.Ft double
	52	.Fn atof_l "const char *str" "locale_t loc"
	53	.Sh DESCRIPTION
	54	The
	55	.Fn atof
	56	function converts the initial portion of the string pointed to by
	57	.Fa str
	58	to
	59	.Vt double
	60	representation.
	61	.Pp
	62	It is equivalent to:
	63	.Bd -literal -offset indent
	64	strtod(str, (char **)NULL);
	65	.Ed
	66	.Pp
	67	The decimal point
	68	character is defined in the program's locale (category
	69	.Dv LC_NUMERIC ) .
	70	.Pp
	71	While the
	72	.Fn atof
	73	function uses the current locale, the
	74	.Fn atof_l
	75	function may be passed a locale directly. See
	76	.Xr xlocale 3
	77	for more information.
	78	.Sh IMPLEMENTATION NOTES
	79	The
	80	.Fn atof
	81	and
	82	.Fn atof_l
	83	functions are thread-safe and async-cancel-safe.
	84	.Pp
	85	The
	86	.Fn atof
	87	and
	88	.Fn atof_l
	89	functions have been deprecated by
	90	.Fn strtod
	91	and
	92	.Fn strtod_l
	93	and should not be used in new code.
	94	.Sh ERRORS
	95	The function
	96	.Fn atof
	97	need not affect the value of
	98	.Va errno
	99	on an error.
	100	.Sh SEE ALSO
	101	.Xr atoi 3 ,
	102	.Xr atol 3 ,
	103	.Xr strtod 3 ,
	104	.Xr strtol 3 ,
	105	.Xr strtoul 3 ,
	106	.Xr xlocale 3
	107	.Sh STANDARDS
	108	The
	109	.Fn atof
	110	function conforms to
	111	.St -p1003.1-90 ,
	112	.St -isoC ,
	113	and
	114	.St -isoC-99 .