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.\" $DragonFly: src/lib/libc/stdlib/atof.3,v 1.2 2003/06/17 04:26:46 dillon Exp $ 35.\" 36.Dd June 4, 1993 37.Dt ATOF 3 38.Os 39.Sh NAME 40.Nm atof 41.Nd convert 42.Tn ASCII 43string to double 44.Sh LIBRARY 45.Lb libc 46.Sh SYNOPSIS 47.In stdlib.h 48.Ft double 49.Fn atof "const char *nptr" 50.Sh DESCRIPTION 51The 52.Fn atof 53function converts the initial portion of the string pointed to by 54.Fa nptr 55to 56.Vt double 57representation. 58.Pp 59It is equivalent to: 60.Bd -literal -offset indent 61strtod(nptr, NULL); 62.Ed 63.Pp 64The decimal point 65character is defined in the program's locale (category 66.Dv LC_NUMERIC ) . 67.Sh IMPLEMENTATION NOTES 68The 69.Fn atof 70function is not thread-safe and also not async-cancel-safe. 71.Pp 72The 73.Fn atof 74function has been deprecated by 75.Fn strtod 76and should not be used in new code. 77.Sh ERRORS 78The function 79.Fn atof 80need not affect the value of 81.Va errno 82on an error. 83.Sh SEE ALSO 84.Xr atoi 3 , 85.Xr atol 3 , 86.Xr strtod 3 , 87.Xr strtol 3 , 88.Xr strtoul 3 89.Sh STANDARDS 90The 91.Fn atof 92function conforms to 93.St -p1003.1-90 , 94.St -isoC , 95and 96.St -isoC-99 . 97