Often one has files
jan1, jan2, ..., jan9, jan10, ... and it feels wrong when
ls(1)
orders them
jan1, jan10, ..., jan2, ..., jan9.
In order to rectify this, GNU introduced the
-v option to
ls(1),
which is implemented using
versionsort(3),
which again uses
strverscmp().

Thus, the task of
strverscmp() is to compare two strings and find the "right" order, while
strcmp(3)
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
strcmp(3)
would have returned (numerical ordering of byte values).
Otherwise, compare both digit strings numerically, where digit strings with
one or more leading zeros are interpreted as if they have a decimal point
in front (so that in particular digit strings with more leading zeros
come before digit strings with fewer leading zeros).
Thus, the ordering is
000, 00, 01, 010, 09, 0, 1, 9, 10.

The
strverscmp() function returns an integer
less than, equal to, or greater than zero if s1
is found, respectively, to be earlier than, equal to,
or later than s2.

This page is part of release 3.44 of the Linux
man-pages project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/man-pages/.