strverscmp - compare two version strings

       For an explanation of the terms used in this section, see attributes(7).
       ┌─────────────────────────────────────────────────────────────────────────────┬───────────────┬─────────┐
       │ Interface                                                                   │ Attribute     │ Value   │
       ├─────────────────────────────────────────────────────────────────────────────┼───────────────┼─────────┤
       │ strverscmp()                                                                │ Thread safety │ MT-Safe │
       └─────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘

       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)
       finds only 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 program below can be used to demonstrate the behavior  of  strverscmp().   It  uses  strverscmp()  to
       compare the two strings given as its command-line arguments.  An example of its use is the following:

           $ ./a.outjan1jan10
           jan1 < jan10

   Programsource

       #define _GNU_SOURCE
       #include <stdio.h>
       #include <stdlib.h>
       #include <string.h>

       int
       main(int argc, char *argv[])
       {
           int res;

           if (argc != 3) {
               fprintf(stderr, "Usage: %s <string1> <string2>\n", argv[0]);
               exit(EXIT_FAILURE);
           }

           res = strverscmp(argv[1], argv[2]);

           printf("%s %s %s\n", argv[1],
                  (res < 0) ? "<" : (res == 0) ? "==" : ">", argv[2]);

           exit(EXIT_SUCCESS);
       }

       Standard C library (libc, -lc)

       strverscmp - compare two version strings

       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.

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

Linux man-pages 6.9.1                              2024-06-15                                      strverscmp(3)

       GNU.

#define_GNU_SOURCE         /* See feature_test_macros(7) */
       #include<string.h>intstrverscmp(constchar*s1,constchar*s2);