Libc-763.11.tar.gz

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

.\" Copyright (c) 1991, 1993
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.\"     @(#)atof.3	8.1 (Berkeley) 6/4/93
.\" $FreeBSD: src/lib/libc/stdlib/atof.3,v 1.17 2007/01/09 00:28:09 imp 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
and
.Fn atof_l
functions are thread-safe and async-cancel-safe.
.Pp
The
.Fn atof
and
.Fn atof_l
functions have been deprecated by
.Fn strtod
and
.Fn strtod_l
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 .