1 .\" Copyright (C) 2001 Andries Brouwer <aeb@cwi.nl>
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25 .TH STRVERSCMP 3 2001-12-19 "GNU" "Linux Programmer's Manual"
27 strverscmp \- compare two version strings
30 .BR "#define _GNU_SOURCE" " /* See feature_test_macros(7) */"
32 .B #include <string.h>
34 .BI "int strverscmp(const char *" s1 ", const char *" s2 );
38 .IR jan1 ", " jan2 ", ..., " jan9 ", " jan10 ", ..."
39 and it feels wrong when
42 .IR jan1 ", " jan10 ", ..., " jan2 ", ..., " jan9 .
43 .\" classical solution: "rename jan jan0 jan?"
44 In order to rectify this, GNU introduced the
48 which is implemented using
55 is to compare two strings and find the "right" order, while
57 finds only the lexicographic order.
58 This function does not use
61 so is meant mostly for situations
62 where the strings are expected to be in ASCII.
64 What this function does is the following.
65 If both strings are equal, return 0.
66 Otherwise, find the position
67 between two bytes with the property that before it both strings are equal,
68 while directly after it there is a difference.
69 Find the largest consecutive digit strings containing (or starting at,
70 or ending at) this position.
71 If one or both of these is empty,
74 would have returned (numerical ordering of byte values).
75 Otherwise, compare both digit strings numerically, where digit strings with
76 one or more leading zeros are interpreted as if they have a decimal point
77 in front (so that in particular digit strings with more leading zeros
78 come before digit strings with fewer leading zeros).
80 .IR 000 ", " 00 ", " 01 ", " 010 ", " 09 ", " 0 ", " 1 ", " 9 ", " 10 .
84 function returns an integer
85 less than, equal to, or greater than zero if
87 is found, respectively, to be earlier than, equal to,
91 This function is a GNU extension.
98 This page is part of release 3.79 of the Linux
101 A description of the project,
102 information about reporting bugs,
103 and the latest version of this page,
105 \%http://www.kernel.org/doc/man\-pages/.