STRVERSCMP(3) Linux Programmer's Manual STRVERSCMP(3)NAMEstrverscmp - compare two version stringsSYNOPSIS#define_GNU_SOURCE#include<string.h>intstrverscmp(constchar*s1,constchar*s2);DESCRIPTIONOften one has filesjan1,jan2, ...,jan9,jan10, ... and it feels wrong when ls(1) orders themjan1,jan10, ...,jan2, ...,jan9. In order to rectify this, GNU introduced the-voption to ls(1), which is implemented using versionsort(3), which again usesstrverscmp(). Thus, the task ofstrverscmp() is to compare two strings and find the "right" order, while strcmp(3) only finds the lexicographic order. This function does not use the locale categoryLC_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 numeri- cally, 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 is000,00,01,010,09,0,1,9,10.RETURNVALUEThestrverscmp() function returns an integer less than, equal to, or greater than zero ifs1is found, respectively, to be earlier than, equal to, or later thans2.CONFORMINGTOThis function is a GNU extension.SEEALSOrename(1), strcasecmp(3), strcmp(3), strcoll(3), feature_test_macros(7)COLOPHONThis page is part of release 3.22 of the Linuxman-pagesproject. A description of the project, and information about reporting bugs, can be found at http://www.ker- nel.org/doc/man-pages/. GNU 2001-12-19 STRVERSCMP(3)

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