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+.\" Copyright (C) 2001 Andries Brouwer <aeb@cwi.nl>
+.\"
+.\" Permission is granted to make and distribute verbatim copies of this
+.\" manual provided the copyright notice and this permission notice are
+.\" preserved on all copies.
+.\"
+.\" Permission is granted to copy and distribute modified versions of this
+.\" manual under the conditions for verbatim copying, provided that the
+.\" entire resulting derived work is distributed under the terms of a
+.\" permission notice identical to this one.
+.\" 
+.\" Since the Linux kernel and libraries are constantly changing, this
+.\" manual page may be incorrect or out-of-date.  The author(s) assume no
+.\" responsibility for errors or omissions, or for damages resulting from
+.\" the use of the information contained herein.  The author(s) may not
+.\" have taken the same level of care in the production of this manual,
+.\" which is licensed free of charge, as they might when working
+.\" professionally.
+.\" 
+.\" Formatted or processed versions of this manual, if unaccompanied by
+.\" the source, must acknowledge the copyright and authors of this work.
+.\"
+.TH STRVERSCMP 3  2001-12-19 "GNU" "Linux Programmer's Manual"
+.SH NAME
+strverscmp \- compare two version strings
+.SH SYNOPSIS
+.nf
+.B #define _GNU_SOURCE
+.br
+.B #include <string.h>
+.sp
+.BI "int strverscmp(const char *" s1 ", const char *" s2 );
+.fi
+.SH DESCRIPTION
+Often one has files
+.IR jan1 ", " jan2 ", ..., " jan9 ", " jan10 ", ..."
+and it feels wrong when
+.B ls
+orders them
+.IR jan1 ", " jan10 ", ..., " jan2 ", ..., " jan9 ".
+.\" classical solution: "rename jan jan0 jan?"
+In order to rectify this, GNU introduced the
+.B \-v
+option to
+.BR ls (1),
+which is implemented using
+.BR versionsort (3),
+which again uses
+.BR strverscmp .
+
+Thus, the task of
+.B strverscmp
+is to compare two strings and find the "right" order, while
+.B strcmp
+only finds the lexicographic order. This function does not use
+the locale category LC_COLLATE, so is meant mostly for situations
+where the strings are expected to be in ASCII.
+
+What this function does is the following.
+If both strings are equal, return 0. Otherwise find the position
+between two bytes with the property that before it both strings are equal,
+while directly after it there is a difference.
+Find the largest consecutive digit strings containing (or starting at,
+or ending at) this position. If one or both of these is empty,
+then return what
+.B strcmp
+would have returned (numerical ordering of byte values).
+Otherwise, compare both digit strings numerically, where digit strings with
+one or more leading zeroes are interpreted as if they have a decimal point
+in front (so that in particular digit strings with more leading zeroes
+come before digit strings with fewer leading zeroes).
+Thus, the ordering is
+.IR 000 ", " 00 ", " 01 ", " 010 ", " 09 ", " 0 ", " 1 ", " 9 ", " 10 .
+.SH "RETURN VALUE"
+The \fBstrverscmp()\fP function returns an integer 
+less than, equal to, or greater than zero if \fIs1\fP
+is found, respectively, to be earlier than, equal to,
+or later than \fIs2\fP.
+.SH "CONFORMING TO"
+This function is a GNU extension.
+.SH "SEE ALSO"
+.BR rename (1),
+.BR strcasecmp (3),
+.BR strcmp (3),
+.BR strcoll (3)