4.4BSD/usr/src/lib/libc/stdlib/atof.3

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.\"     @(#)atof.3	8.1 (Berkeley) 6/4/93
.\"
.Dd June 4, 1993
.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.