minix/lib/libc/stdlib/strtoul.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

263 lines
6.1 KiB
Groff

.\" $NetBSD: strtoul.3,v 1.25 2009/12/02 12:50:27 pooka 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
.\" Chris Torek and the American National Standards Committee X3,
.\" on Information Processing Systems.
.\"
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.\" modification, are permitted provided that the following conditions
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.\" notice, this list of conditions and the following disclaimer.
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.\" notice, this list of conditions and the following disclaimer in the
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.\" 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.
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.\" 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
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.\" 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: @(#)strtoul.3 8.1 (Berkeley) 6/4/93
.\"
.Dd December 2, 2009
.Dt STRTOUL 3
.Os
.Sh NAME
.Nm strtoul ,
.Nm strtoull ,
.Nm strtoumax ,
.Nm strtouq
.Nd convert a string to an unsigned long, unsigned long long, uintmax_t or uquad_t integer
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In stdlib.h
.In limits.h
.Ft unsigned long int
.Fn strtoul "const char * restrict nptr" "char ** restrict endptr" "int base"
.Ft unsigned long long int
.Fn strtoull "const char * restrict nptr" "char ** restrict endptr" "int base"
.Pp
.In inttypes.h
.Ft uintmax_t
.Fn strtoumax "const char * restrict nptr" "char ** restrict endptr" "int base"
.Pp
.In sys/types.h
.In stdlib.h
.In limits.h
.Ft u_quad_t
.Fn strtouq "const char * restrict nptr" "char ** restrict endptr" "int base"
.Sh DESCRIPTION
The
.Fn strtoul
function
converts the string in
.Fa nptr
to an
.Ft unsigned long int
value.
The
.Fn strtoull
function
converts the string in
.Fa nptr
to an
.Ft unsigned long long int
value.
The
.Fn strtoumax
function
converts the string in
.Fa nptr
to an
.Ft uintmax_t
value.
The
.Fn strtouq
function
converts the string in
.Fa nptr
to a
.Ft u_quad_t
value.
The conversion is done according to the given
.Fa base ,
which must be between 2 and 36 inclusive,
or be the special value 0.
.Pp
The string may begin with an arbitrary amount of white space
(as determined by
.Xr isspace 3 )
followed by a single optional
.Ql +
or
.Ql -
sign.
If
.Fa base
is zero or 16,
the string may then include a
.Ql 0x
prefix,
and the number will be read in base 16; otherwise, a zero
.Fa base
is taken as 10 (decimal) unless the next character is
.Ql 0 ,
in which case it is taken as 8 (octal).
.Pp
The remainder of the string is converted to an
.Em unsigned long
value in the obvious manner,
stopping at the end of the string
or at the first character that does not produce a valid digit
in the given base.
(In bases above 10, the letter
.Ql A
in either upper or lower case
represents 10,
.Ql B
represents 11, and so forth, with
.Ql Z
representing 35.)
.Pp
If
.Fa endptr
is non-nil,
.Fn strtoul
stores the address of the first invalid character in
.Fa *endptr .
If there were no digits at all, however,
.Fn strtoul
stores the original value of
.Fa nptr
in
.Fa *endptr .
(Thus, if
.Fa *nptr
is not
.Ql \e0
but
.Fa **endptr
is
.Ql \e0
on return, the entire string was valid.)
.Sh RETURN VALUES
The
.Fn strtoul
function
returns either the result of the conversion
or, if there was a leading minus sign,
the negation of the result of the conversion,
unless the original (non-negated) value would overflow;
in the latter case,
.Fn strtoul
returns
.Dv ULONG_MAX ,
.Fn strtoull
returns
.Dv ULLONG_MAX ,
.Fn strtoumax
returns
.Dv UINTMAX_MAX ,
.Fn strtouq
returns
.Dv UQUAD_MAX ,
and the global variable
.Va errno
is set to
.Er ERANGE .
.Pp
There is no way to determine if
.Fn strtoul
has processed a negative number (and returned an unsigned value) short of
examining the string in
.Fa nptr
directly.
If the
.Fa base
argument is not supported then
.Va errno
is set to
.Er EINVAL
and the functions return 0.
.Pp
If no error occurs,
.Va errno
is left unchanged.
This behavior (which is unlike most library functions) is guaranteed
by the pertinent standards.
.Sh EXAMPLES
Because the return value of
.Fn strtoul
cannot be used unambiguously to detect an error,
.Va errno
is left unchanged after a successful call.
To ensure that a string is a valid number (i.e., in range and containing no
trailing characters), clear
.Va errno
beforehand explicitly, then check it afterwards:
.Bd -literal -offset indent
char *ep;
unsigned long ulval;
\&...
errno = 0;
ulval = strtoul(buf, \*[Am]ep, 10);
if (buf[0] == '\e0' || *ep != '\e0')
goto not_a_number;
if (errno == ERANGE \*[Am]\*[Am] ulval == ULONG_MAX)
goto out_of_range;
.Ed
.Pp
This example will accept
.Dq 12
but not
.Dq 12foo
or
.Dq 12\en .
If trailing whitespace is acceptable, further checks must be done on
.Va *ep ;
alternately, use
.Xr sscanf 3 .
.Sh ERRORS
.Bl -tag -width Er
.It Bq Er EINVAL
The
.Ar base
is not between 2 and 36 and does not contain the special value 0.
.It Bq Er ERANGE
The given string was out of range; the value converted has been clamped.
.El
.Sh SEE ALSO
.Xr strtoimax 3 ,
.Xr strtol 3 ,
.Xr strtoll 3
.Sh STANDARDS
The
.Fn strtoul
function
conforms to
.St -ansiC .
The
.Fn strtoull
and
.Fn strtoumax
functions conform to
.St -isoC-99 .
.Sh BUGS
Ignores the current locale.