141 lines
4.5 KiB
Groff
141 lines
4.5 KiB
Groff
.\" Copyright (c) 1990, 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.
|
|
.\"
|
|
.\" @(#)strtod.3 8.1 (Berkeley) 6/4/93
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd June 4, 1993
|
|
.Dt STRTOD 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm strtod
|
|
.Nd convert
|
|
.Tn ASCII
|
|
string to double
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In stdlib.h
|
|
.Ft double
|
|
.Fn strtod "const char *nptr" "char **endptr"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn strtod
|
|
function converts the initial portion of the string
|
|
pointed to by
|
|
.Fa nptr
|
|
to
|
|
.Em double
|
|
representation.
|
|
.Pp
|
|
The expected form of the string is an optional plus (``+'') or minus
|
|
sign (``\-'') followed by a sequence of digits optionally containing
|
|
a decimal-point character, optionally followed by an exponent.
|
|
An exponent consists of an ``E'' or ``e'', followed by an optional plus
|
|
or minus sign, followed by a sequence of digits.
|
|
.Pp
|
|
Leading white-space characters in the string (as defined by the
|
|
.Xr isspace 3
|
|
function) are skipped.
|
|
The decimal point
|
|
character is defined in the program's locale (category
|
|
.Dv LC_NUMERIC ) .
|
|
.Sh RETURN VALUES
|
|
The
|
|
.Fn strtod
|
|
function returns the converted value, if any.
|
|
.Pp
|
|
If
|
|
.Fa endptr
|
|
is not
|
|
.Dv NULL ,
|
|
a pointer to the character after the last character used
|
|
in the conversion is stored in the location referenced by
|
|
.Fa endptr .
|
|
.Pp
|
|
If no conversion is performed, zero is returned and the value of
|
|
.Fa nptr
|
|
is stored in the location referenced by
|
|
.Fa endptr .
|
|
.Pp
|
|
If the correct value would cause overflow, plus or minus
|
|
.Dv HUGE_VAL
|
|
is returned (according to the sign of the value), and
|
|
.Er ERANGE
|
|
is stored in
|
|
.Va errno .
|
|
If the correct value would cause underflow, zero is
|
|
returned and
|
|
.Er ERANGE
|
|
is stored in
|
|
.Va errno .
|
|
.Sh ERRORS
|
|
.Bl -tag -width Er
|
|
.It Bq Er ERANGE
|
|
Overflow or underflow occurred.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr atof 3 ,
|
|
.Xr atoi 3 ,
|
|
.Xr atol 3 ,
|
|
.Xr strtol 3 ,
|
|
.Xr strtoul 3
|
|
.Sh STANDARDS
|
|
The
|
|
.Fn strtod
|
|
function
|
|
conforms to
|
|
.St -isoC .
|
|
.Sh AUTHORS
|
|
The author of this software is
|
|
.An David M. Gay .
|
|
.Pp
|
|
Copyright (c) 1991 by AT&T.
|
|
.Pp
|
|
Permission to use, copy, modify, and distribute this software for any
|
|
purpose without fee is hereby granted, provided that this entire notice
|
|
is included in all copies of any software which is or includes a copy
|
|
or modification of this software and in all copies of the supporting
|
|
documentation for such software.
|
|
.Pp
|
|
THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
|
|
WARRANTY. IN PARTICULAR, NEITHER THE AUTHOR NOR AT&T MAKES ANY
|
|
REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
|
|
OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
|
|
.Pp
|
|
Contact your vendor for a free copy of the source code to
|
|
.Fn strtod
|
|
and accompanying functions.
|