.\" 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 .Nd convert .Tn ASCII string to double .Sh LIBRARY .Lb libc .Sh SYNOPSIS .In stdlib.h .Ft double .Fn atof "const char *nptr" .Sh DESCRIPTION The .Fn atof function converts the initial portion of the string pointed to by .Fa nptr to .Vt double representation. .Pp It is equivalent to: .Bd -literal -offset indent strtod(nptr, (char **)NULL); .Ed .Pp The decimal point character is defined in the program's locale (category .Dv LC_NUMERIC ) . .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 .Sh STANDARDS The .Fn atof function conforms to .St -p1003.1-90 , .St -isoC , and .St -isoC-99 .