[apple/libc.git] / stdlib / atof.3

.\" Copyright (c) 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" the American National Standards Committee X3, on Information
.\" Processing Systems.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)atof.3	8.1 (Berkeley) 6/4/93
.\" $FreeBSD: src/lib/libc/stdlib/atof.3,v 1.16 2002/12/18 13:33:03 ru Exp $
.\"
.Dd June 4, 1993
.Dt ATOF 3
.Os
.Sh NAME
.Nm atof ,
.Nm atof_l
.Nd convert
.Tn ASCII
string to double
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In stdlib.h
.Ft double
.Fn atof "const char *str"
.In xlocale.h
.Ft double
.Fn atof_l "const char *str" "locale_t loc"
.Sh DESCRIPTION
The
.Fn atof
function converts the initial portion of the string pointed to by
.Fa str
to
.Vt double
representation.
.Pp
It is equivalent to:
.Bd -literal -offset indent
strtod(str, (char **)NULL);
.Ed
.Pp
The decimal point
character is defined in the program's locale (category
.Dv LC_NUMERIC ) .
.Pp
While the
.Fn atof
function uses the current locale, the
.Fn atof_l
function may be passed a locale directly. See
.Xr xlocale 3
for more information.
.Sh IMPLEMENTATION NOTES
The
.Fn atof
function is not thread-safe and also not async-cancel-safe.
.Pp
The
.Fn atof
function has been deprecated by
.Fn strtod
and should not be used in new code.
.Sh ERRORS
The function
.Fn atof
need not affect the value of
.Va errno
on an error.
.Sh SEE ALSO
.Xr atoi 3 ,
.Xr atol 3 ,
.Xr strtod 3 ,
.Xr strtol 3 ,
.Xr strtoul 3 ,
.Xr xlocale 3
.Sh STANDARDS
The
.Fn atof
function conforms to
.St -p1003.1-90 ,
.St -isoC ,
and
.St -isoC-99 .
Commit	Line	Data
224c7076	1	.\" Copyright (c) 1991, 1993
e9ce8d39 A	2	.\" The Regents of the University of California. All rights reserved.
e9ce8d39 A	3	.\"
224c7076 A	4	.\" This code is derived from software contributed to Berkeley by
	5	.\" the American National Standards Committee X3, on Information
	6	.\" Processing Systems.
	7	.\"
e9ce8d39 A	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	.\" 3. All advertising materials mentioning features or use of this software
	17	.\" must display the following acknowledgement:
	18	.\" This product includes software developed by the University of
	19	.\" California, Berkeley and its contributors.
	20	.\" 4. Neither the name of the University nor the names of its contributors
	21	.\" may be used to endorse or promote products derived from this software
	22	.\" without specific prior written permission.
	23	.\"
	24	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	25	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	26	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	27	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	28	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	29	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	30	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	31	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	32	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	33	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	34	.\" SUCH DAMAGE.
	35	.\"
224c7076 A	36	.\" @(#)atof.3 8.1 (Berkeley) 6/4/93
224c7076 A	37	.\" $FreeBSD: src/lib/libc/stdlib/atof.3,v 1.16 2002/12/18 13:33:03 ru Exp $
e9ce8d39	38	.\"
5b2abdfb	39	.Dd June 4, 1993
224c7076	40	.Dt ATOF 3
e9ce8d39 A	41	.Os
e9ce8d39 A	42	.Sh NAME
224c7076 A	43	.Nm atof ,
	44	.Nm atof_l
	45	.Nd convert
	46	.Tn ASCII
	47	string to double
e9ce8d39 A	48	.Sh LIBRARY
	49	.Lb libc
	50	.Sh SYNOPSIS
224c7076 A	51	.In stdlib.h
	52	.Ft double
	53	.Fn atof "const char *str"
	54	.In xlocale.h
	55	.Ft double
	56	.Fn atof_l "const char *str" "locale_t loc"
e9ce8d39 A	57	.Sh DESCRIPTION
e9ce8d39 A	58	The
224c7076 A	59	.Fn atof
	60	function converts the initial portion of the string pointed to by
	61	.Fa str
	62	to
	63	.Vt double
	64	representation.
	65	.Pp
	66	It is equivalent to:
	67	.Bd -literal -offset indent
	68	strtod(str, (char **)NULL);
	69	.Ed
	70	.Pp
	71	The decimal point
	72	character is defined in the program's locale (category
	73	.Dv LC_NUMERIC ) .
	74	.Pp
	75	While the
	76	.Fn atof
	77	function uses the current locale, the
	78	.Fn atof_l
	79	function may be passed a locale directly. See
	80	.Xr xlocale 3
	81	for more information.
	82	.Sh IMPLEMENTATION NOTES
e9ce8d39	83	The
224c7076 A	84	.Fn atof
	85	function is not thread-safe and also not async-cancel-safe.
	86	.Pp
5b2abdfb	87	The
224c7076 A	88	.Fn atof
	89	function has been deprecated by
	90	.Fn strtod
	91	and should not be used in new code.
	92	.Sh ERRORS
	93	The function
	94	.Fn atof
	95	need not affect the value of
	96	.Va errno
	97	on an error.
e9ce8d39	98	.Sh SEE ALSO
224c7076 A	99	.Xr atoi 3 ,
	100	.Xr atol 3 ,
	101	.Xr strtod 3 ,
	102	.Xr strtol 3 ,
	103	.Xr strtoul 3 ,
	104	.Xr xlocale 3
	105	.Sh STANDARDS
5b2abdfb	106	The
224c7076 A	107	.Fn atof
	108	function conforms to
	109	.St -p1003.1-90 ,
	110	.St -isoC ,
	111	and
	112	.St -isoC-99 .