usr/src/lib/libc/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.
.\"
.\" %sccs.include.redist.man%
.\"
.\"     @(#)atof.3      8.1 (Berkeley) %G%
.\"
.Dd
.Dt ATOF 3
.Os
.Sh NAME
.Nm atof
.Nd convert
.Tn ASCII
string to double
.Sh SYNOPSIS
.Fd #include <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
.Ar nptr
to
.Ar double
representation.
.Pp
It is equivalent to:
.Bd -literal -offset indent
strtod(nptr, (char **)NULL);
.Ed
.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 -ansiC .
.Sh BUGS
This manual page represents intent instead of actual practice.
While it is intended that
.Fn atof
be implemented using
.Xr strtod 3 ,
this has not yet happened.
In the current system,
.Fn atof
translates a string in the following form to a double: a string of
leading white space, possibly followed by a sign (``+'' or ``-''),
followed by a digit string which may contain one decimal point (``.''),
which may be followed by either of the exponent flags (``E'' or ``e''),
and lastly, followed by a signed or unsigned integer.