NAME

       strverscmp - compare two version strings

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #define _GNU_SOURCE         /* See feature_test_macros(7) */
       #include <string.h>

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

DESCRIPTION

       For  a  dataset  like jan1, jan2, ..., jan9, jan10, ...  sorting it lexicographically yields jan1, jan10,
       ..., jan2, ..., jan9.  The task of strverscmp() is to compare two  strings  yielding  the  former  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.   This  is
       different from the ordering produced by sort(1) -V.

       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.

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.

ATTRIBUTES

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

STANDARDS

       GNU.

EXAMPLES

       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.out jan1 jan10;
           jan1 < jan10

   Program source

       #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);
       }

SEE ALSO

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

Linux man-pages 6.16                               2025-09-25                                      strverscmp(3)