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.\" 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.\" 36.\" @(#)atof.3 8.1 (Berkeley) 6/4/93 37.\" $FreeBSD$ 38.\" 39.Dd June 4, 1993 40.Dt ATOF 3 41.Os 42.Sh NAME 43.Nm atof 44.Nd convert 45.Tn ASCII 46string to double 47.Sh LIBRARY 48.Lb libc 49.Sh SYNOPSIS 50.In stdlib.h 51.Ft double 52.Fn atof "const char *nptr" 53.Sh DESCRIPTION 54The 55.Fn atof 56function converts the initial portion of the string pointed to by 57.Fa nptr 58to 59.Vt double 60representation. 61.Pp 62It is equivalent to: 63.Bd -literal -offset indent 64strtod(nptr, (char **)NULL); 65.Ed 66.Pp 67The decimal point 68character is defined in the program's locale (category 69.Dv LC_NUMERIC ) . 70.Sh IMPLEMENTATION NOTES 71The 72.Fn atof 73function is not thread-safe and also not async-cancel-safe. 74.Pp 75The 76.Fn atof 77function has been deprecated by 78.Fn strtod 79and should not be used in new code. 80.Sh ERRORS 81The function 82.Fn atof 83need not affect the value of 84.Va errno 85on an error. 86.Sh SEE ALSO 87.Xr atoi 3 , 88.Xr atol 3 , 89.Xr strtod 3 , 90.Xr strtol 3 , 91.Xr strtoul 3 92.Sh STANDARDS 93The 94.Fn atof 95function conforms to 96.St -p1003.1-90 , 97.St -isoC , 98and 99.St -isoC-99 . 100