[src/trunk]: src/lib/libc/stdlib man page for strtonum.3

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/6fbd936509bc
branches:  trunk
changeset: 335642:6fbd936509bc
user:      christos <christos%NetBSD.org@localhost>
date:      Sun Jan 18 17:59:36 2015 +0000

description:
man page for strtonum.3

diffstat:

 lib/libc/stdlib/Makefile.inc |    5 +-
 lib/libc/stdlib/strtonum.3   |  187 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 190 insertions(+), 2 deletions(-)

diffs (210 lines):

diff -r 38059dd4b67c -r 6fbd936509bc lib/libc/stdlib/Makefile.inc
--- a/lib/libc/stdlib/Makefile.inc      Sun Jan 18 17:56:09 2015 +0000
+++ b/lib/libc/stdlib/Makefile.inc      Sun Jan 18 17:59:36 2015 +0000
@@ -1,4 +1,4 @@
-#      $NetBSD: Makefile.inc,v 1.85 2015/01/16 18:41:33 christos Exp $
+#      $NetBSD: Makefile.inc,v 1.86 2015/01/18 17:59:36 christos Exp $
 #      from: @(#)Makefile.inc  8.3 (Berkeley) 2/4/95
 
 # stdlib sources
@@ -53,7 +53,8 @@
        posix_memalign.3 posix_openpt.3 ptsname.3 \
        qabs.3 qdiv.3 quick_exit.3 qsort.3 \
        radixsort.3 rand48.3 rand.3 random.3 \
-       strfmon.3 strsuftoll.3 strtod.3 strtol.3 strtoul.3 system.3 \
+       strfmon.3 strsuftoll.3 strtod.3 strtol.3 strtoul.3 strtonum.3 \
+       system.3 \
        tsearch.3 \
        unlockpt.3
 
diff -r 38059dd4b67c -r 6fbd936509bc lib/libc/stdlib/strtonum.3
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/libc/stdlib/strtonum.3        Sun Jan 18 17:59:36 2015 +0000
@@ -0,0 +1,187 @@
+.\" $NetBSD: strtonum.3,v 1.1 2015/01/18 17:59:36 christos Exp $
+.\" $OpenBSD: strtonum.3,v 1.17 2013/08/14 06:32:28 jmc Exp $
+.\"
+.\" Copyright (c) 2004 Ted Unangst
+.\"
+.\" Permission to use, copy, modify, and distribute this software for any
+.\" purpose with or without fee is hereby granted, provided that the above
+.\" copyright notice and this permission notice appear in all copies.
+.\"
+.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+.\"
+.Dd $Mdocdate: August 14 2013 $
+.Dt STRTONUM 3
+.Os
+.Sh NAME
+.Nm strtonum
+.Nd reliably convert string value to an integer
+.Sh SYNOPSIS
+.Vt #define _OPENBSD_SOURCE
+.In stdlib.h
+.Ft long long
+.Fo strtonum
+.Fa "const char *nptr"
+.Fa "long long minval"
+.Fa "long long maxval"
+.Fa "const char **errstr"
+.Fc
+.Sh DESCRIPTION
+The
+.Fn strtonum
+function converts the string in
+.Fa nptr
+to a
+.Li long long
+value.
+.Pp
+The string may begin with an arbitrary amount of whitespace
+(as determined by
+.Xr isspace 3 )
+followed by a single optional
+.Ql +
+or
+.Ql -
+sign.
+.Pp
+The remainder of the string is converted to a
+.Li long long
+value according to base 10.
+.Pp
+The value obtained is then checked against the provided
+.Fa minval
+and
+.Fa maxval
+bounds.
+If
+.Fa errstr
+is non-null,
+.Fn strtonum
+stores an error string in
+.Fa *errstr
+indicating the failure.
+.Sh RETURN VALUES
+The
+.Fn strtonum
+function returns the result of the conversion,
+unless the value would exceed the provided bounds or is invalid.
+On error, 0 is returned,
+.Va errno
+is set, and
+.Fa errstr
+will point to an error message.
+.Fa *errstr
+will be set to
+.Dv NULL
+on success;
+this fact can be used to differentiate
+a successful return of 0 from an error.
+.Sh EXAMPLES
+Using
+.Fn strtonum
+correctly is meant to be simpler than the alternative functions.
+.Bd -literal -offset indent
+int iterations;
+const char *errstr;
+
+iterations = strtonum(optarg, 1, 64, &errstr);
+if (errstr)
+       errx(1, "number of iterations is %s: %s", errstr, optarg);
+.Ed
+.Pp
+The above example will guarantee that the value of iterations is between
+1 and 64 (inclusive).
+.Sh ERRORS
+.Bl -tag -width Er
+.It Bq Er ERANGE
+The given string was out of range.
+.It Bq Er EINVAL
+The given string did not consist solely of digit characters.
+.It Bq Er EINVAL
+.Ar minval
+was larger than
+.Ar maxval .
+.El
+.Pp
+If an error occurs,
+.Fa errstr
+will be set to one of the following strings:
+.Pp
+.Bl -tag -width "too largeXX" -compact
+.It Qq too large
+The result was larger than the provided maximum value.
+.It Qq too small
+The result was smaller than the provided minimum value.
+.It Qq invalid
+The string did not consist solely of digit characters.
+.El
+.Sh CAVEATS
+The
+.Fn strtonum
+function was designed to facilitate safe,
+robust programming and overcome the shortcomings of the
+.Xr atoi 3
+and
+.Xr strtol 3
+family of interfaces, however there are problems with the
+.Fn strtonum
+API:
+.Bl -dash
+.It
+will return 0 on failure; 0 might not be in range, so that necessitates an error check even if you want to avoid it
+.It
+does not differentiate 'illegal' returns, so we can't tell the difference between partial and no conversions
+.It
+returns english strings
+.It
+can't set the base, or find where the conversion ended
+.It
+hardcodes long long integer type
+.El
+To overcome the shortcomings of
+.Fn strtonum
+.Nx
+provides
+.Fn strtou 3
+and
+.Fn strtoi 3 .
+.Sh SEE ALSO
+.Xr atof 3 ,
+.Xr atoi 3 ,
+.Xr atol 3 ,
+.Xr atoll 3 ,
+.Xr sscanf 3 ,
+.Xr strtoi 3 ,
+.Xr strtod 3 ,
+.Xr strtol 3 ,
+.Xr strtoll 3 ,
+.Xr strtou 3 ,
+.Xr strtoul 3
+.Xr strtoull 3
+.Sh STANDARDS
+.Fn strtonum
+is an
+.Ox
+extension.
+.Sh HISTORY
+The
+.Fn strtonum
+function first appeared in
+.Ox 3.6 .
+.Fn strtonum
+was redesigned in
+.Nx 8
+as
+.Fn strtoi 3
+and
+.Fn strtou 3 .
+For compatibility reasons it's available since
+.Nx 8
+in the
+.Vt _OPENBSD_SOURCE
+namespace.