minix/lib/libc/stdlib/strtod.3
Ben Gras 2fe8fb192f Full switch to clang/ELF. Drop ack. Simplify.
There is important information about booting non-ack images in
docs/UPDATING. ack/aout-format images can't be built any more, and
booting clang/ELF-format ones is a little different. Updating to the
new boot monitor is recommended.

Changes in this commit:

	. drop boot monitor -> allowing dropping ack support
	. facility to copy ELF boot files to /boot so that old boot monitor
	  can still boot fairly easily, see UPDATING
	. no more ack-format libraries -> single-case libraries
	. some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases
	. drop several ack toolchain commands, but not all support
	  commands (e.g. aal is gone but acksize is not yet).
	. a few libc files moved to netbsd libc dir
	. new /bin/date as minix date used code in libc/
	. test compile fix
	. harmonize includes
	. /usr/lib is no longer special: without ack, /usr/lib plays no
	  kind of special bootstrapping role any more and bootstrapping
	  is done exclusively through packages, so releases depend even
	  less on the state of the machine making them now.
	. rename nbsd_lib* to lib*
	. reduce mtree
2012-02-14 14:52:02 +01:00

198 lines
4.7 KiB
Groff

.\" $NetBSD: strtod.3,v 1.20 2007/10/24 13:42:10 reed Exp $
.\"
.\" 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. 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.
.\"
.\" from: @(#)strtod.3 8.1 (Berkeley) 6/4/93
.\"
.Dd March 12, 2006
.Dt STRTOD 3
.Os
.Sh NAME
.Nm strtod ,
.Nm strtof ,
.Nm strtold
.Nd convert
.Tn ASCII
string to double, float, or long double
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In stdlib.h
.Ft double
.Fn strtod "const char * restrict nptr" "char ** restrict endptr"
.Ft float
.Fn strtof "const char * restrict nptr" "char ** restrict endptr"
.Ft long double
.Fn strtold "const char * restrict nptr" "char ** restrict 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
.Fn strtof
function converts the initial portion of the string
pointed to by
.Fa nptr
to
.Em float
representation.
.Pp
The
.Fn strtold
function converts the initial portion of the string
pointed to by
.Fa nptr
to
.Em long double
representation.
.Pp
The expected form of the string is an optional plus
.Pq Sq +
or minus sign
.Pq Sq \-
followed by one of the following:
.Bl -dash
.It
a sequence of digits optionally containing
a decimal-point character, optionally followed by an exponent.
An exponent consists of an
.Sq E
or
.Sq e ,
followed by an optional plus
or minus sign, followed by a sequence of digits.
.It
one of
.Li INF
or
.Li INFINITY ,
ignoring case.
.It
one of
.Li NAN
or
.Li NAN(n-char-sequence-opt) ,
ignoring case.
This implementation currently does not interpret such a sequence.
.El
.Pp
Leading white-space characters in the string (as defined by the
.Xr isspace 3
function) are skipped.
.Sh RETURN VALUES
The
.Fn strtod ,
.Fn strtof ,
and
.Fn strtold
functions return the converted value, if any.
.Pp
A character sequence
.Li INF
or
.Li INFINITY
is converted to \*(If,
if supported, else to the largest finite floating-point number representable
on the machine (i.e.,
.Tn VAX ) .
.Pp
A character sequence
.Li NAN
or
.Li NAN(n-char-sequence-opt)
is converted to a quiet \*(Na, if supported, else remains unrecognized (i.e.,
.Tn VAX ) .
.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 ,
.Dv HUGE_VALF ,
or
.Dv HUGE_VALL
is returned (according to the return type and sign of the value), and
.Dv ERANGE
is stored in
.Va errno .
If the correct value would cause underflow, zero is
returned and
.Dv 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 math 3 ,
.Xr strtol 3 ,
.Xr strtoul 3
.Sh STANDARDS
The
.Fn strtod
function
conforms to
.St -ansiC .
The
.Fn strtof
and
.Fn strtold
functions conform to
.St -isoC-99 .
.Sh HISTORY
The
.Fn strtof
and
.Fn strtold
functions appeared in
.Nx 4.0 .