strverscmp

<html> <head> <title>strverscmp</title> <META NAME="KEYWORDS" CONTENT="strverscmp"> </head> <body BGCOLOR="#ffffff" LINK="#0000ff" VLINK="#0000ff" ALINK="#0000ff" TEXT="#000000"> <center> <h1>strverscmp</h1></center> <PRE> <A HREF="/man3/STRVERSCMP">STRVERSCMP(3)</A> Linux Programmer's Manual <A HREF="/man3/STRVERSCMP">STRVERSCMP(3)</A> NAME strverscmp - compare two version strings SYNOPSIS #define _GNU_SOURCE /* See <A HREF="/man7/feature_test_macros">feature_test_macros(7)</A> */ #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 <A HREF="/man1/ls">ls(1)</A> orders them jan1, jan10, ..., jan2, ..., jan9. In or- der to rectify this, GNU introduced the -v option to <A HREF="/man1/ls">ls(1)</A>, which is implemented using <A HREF="/man3/versionsort">versionsort(3)</A>, which again uses strverscmp(). Thus, the task of strverscmp() is to compare two strings and find the "right" order, while <A HREF="/man3/strcmp">strcmp(3)</A> 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 con- taining (or starting at, or ending at) this position. If one or both of these is empty, then return what <A HREF="/man3/strcmp">strcmp(3)</A> would have returned (nu- merical 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 at- <A HREF="/man7/tributes">tributes(7)</A>. +-------------+---------------+---------+ |Interface | Attribute | Value | +-------------+---------------+---------+ |strverscmp() | Thread safety | MT-Safe | +-------------+---------------+---------+ CONFORMING TO This function is a GNU extension. EXAMPLE The program below can be used to demonstrate the behavior of strver- scmp(). 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 <string.h> #include <stdio.h> #include <stdlib.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 <A HREF="/man1/rename">rename(1)</A>, <A HREF="/man3/strcasecmp">strcasecmp(3)</A>, <A HREF="/man3/strcmp">strcmp(3)</A>, <A HREF="/man3/strcoll">strcoll(3)</A> COLOPHON This page is part of release 5.05 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/. GNU 2019-03-06 <A HREF="/man3/STRVERSCMP">STRVERSCMP(3)</A></PRE> <center> <h6>Man Pages Copyright Respective Owners. Site Copyright (C) 1994 - 2025 <a href="http://www.he.net">Hurricane Electric</a>. All Rights Reserved.</h6></center> </body> </html>

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strverscmp