minix/lib/libc/stdlib/strtol.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

294 lines
6.5 KiB
Groff

.\" $NetBSD: strtol.3,v 1.26 2009/07/23 13:38:57 wiz 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
.\" 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: @(#)strtol.3 8.1 (Berkeley) 6/4/93
.\"
.Dd July 23, 2009
.Dt STRTOL 3
.Os
.Sh NAME
.Nm strtol ,
.Nm strtoll ,
.Nm strtoimax ,
.Nm strtoq
.Nd convert string value to a long, long long, intmax_t or quad_t integer
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In stdlib.h
.In limits.h
.Ft long int
.Fn strtol "const char * restrict nptr" "char ** restrict endptr" "int base"
.Ft long long int
.Fn strtoll "const char * restrict nptr" "char ** restrict endptr" "int base"
.Pp
.In inttypes.h
.Ft intmax_t
.Fn strtoimax "const char * restrict nptr" "char ** restrict endptr" "int base"
.Pp
.In sys/types.h
.In stdlib.h
.In limits.h
.Ft quad_t
.Fn strtoq "const char * restrict nptr" "char ** restrict endptr" "int base"
.Sh DESCRIPTION
The
.Fn strtol
function
converts the string in
.Fa nptr
to a
.Ft long int
value.
The
.Fn strtoll
function
converts the string in
.Fa nptr
to a
.Ft long long int
value.
The
.Fn strtoimax
function
converts the string in
.Fa nptr
to an
.Ft intmax_t
value.
The
.Fn strtoq
function
converts the string in
.Fa nptr
to a
.Ft 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 a
.Em long
value in the obvious manner,
stopping at the first character which is not 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 strtol
stores the address of the first invalid character in
.Fa *endptr .
If there were no digits at all, however,
.Fn strtol
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 strtol
function
returns the result of the conversion,
unless the value would underflow or overflow.
If an underflow occurs,
.Fn strtol
returns
.Dv LONG_MIN ,
.Fn strtoll
returns
.Dv LLONG_MIN ,
and
.Fn strtoimax
returns
.Dv INTMAX_MIN .
If an overflow occurs,
.Fn strtol
returns
.Dv LONG_MAX ,
.Fn strtoll
returns
.Dv LLONG_MAX ,
and
.Fn strtoimax
returns
.Dv INTMAX_MAX .
In these cases,
.Va errno
is set to
.Er ERANGE .
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 strtol
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;
long lval;
\&...
errno = 0;
lval = strtol(buf, \*[Am]ep, 10);
if (buf[0] == '\e0' || *ep != '\e0')
goto not_a_number;
if (errno == ERANGE \*[Am]\*[Am] (lval == LONG_MAX || lval == LONG_MIN))
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 .
.Pp
If
.Fn strtol
is being used instead of
.Xr atoi 3 ,
error checking is further complicated because the desired return value is an
.Li int
rather than a
.Li long ;
however, on some architectures integers and long integers are the same size.
Thus the following is necessary:
.Bd -literal -offset indent
char *ep;
int ival;
long lval;
\&...
errno = 0;
lval = strtol(buf, \*[Am]ep, 10);
if (buf[0] == '\e0' || *ep != '\e0')
goto not_a_number;
if ((errno == ERANGE \*[Am]\*[Am] (lval == LONG_MAX || lval == LONG_MIN)) ||
(lval \*[Gt] INT_MAX || lval \*[Lt] INT_MIN))
goto out_of_range;
ival = lval;
.Ed
.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 atof 3 ,
.Xr atoi 3 ,
.Xr atol 3 ,
.Xr atoll 3 ,
.Xr strtod 3 ,
.Xr strtoul 3 ,
.Xr strtoull 3 ,
.Xr strtoumax 3
.Sh STANDARDS
The
.Fn strtol
function
conforms to
.St -ansiC .
The
.Fn strtoll
and
.Fn strtoimax
functions conform to
.St -isoC-99 .
.Sh BUGS
Ignores the current locale.