NOTE: click here if you get an empty page.

STRVERSCMP(3)		   Linux Programmer's Manual		 STRVERSCMP(3)

NAME
       strverscmp - compare two version strings

SYNOPSIS
       #define _GNU_SOURCE
       #include <string.h>

       int strverscmp(const char *s1, const char *s2);

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

       Thus, the task of strverscmp() is to compare two strings and  find  the
       "right"	order, while 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	 prop-
       erty  that  before  it  both strings are equal, while directly after it
       there is a difference.  Find the largest consecutive digit strings con-
       taining (or starting at, or ending at) this position. If one or both of
       these is empty, then return what strcmp() would have returned  (numeri-
       cal  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 par-
       ticular digit strings  with  more  leading  zeroes  come	 before	 digit
       strings with fewer leading zeroes).  Thus, the ordering is 000, 00, 01,
       010, 09, 0, 1, 9, 10.

RETURN VALUE
       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.

CONFORMING TO
       This function is a GNU extension.

SEE ALSO
       rename(1), strcasecmp(3), strcmp(3), strcoll(3)

GNU				  2001-12-19			 STRVERSCMP(3)