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**NAME**

strverscmp - compare two version strings

**SYNOPSIS**

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

**DESCRIPTION**

Often one has filesjan1,jan2, ...,jan9,jan10, ... and it feels wrong whenls(1) orders themjan1,jan10, ...,jan2, ...,jan9. In order to rectify this, GNU introduced the-voption tols(1), which is implemented usingversionsort(3), which again usesstrverscmp(). Thus, the task ofstrverscmp() is to compare two strings and find the "right" order, whilestrcmp(3) finds only 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 whatstrcmp(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 is000,00,01,010,09,0,1,9,10.

**RETURN** **VALUE**

Thestrverscmp() function returns an integer less than, equal to, or greater than zero ifs1is found, respectively, to be earlier than, equal to, or later thans2.

**CONFORMING** **TO**

This function is a GNU extension.

**SEE** **ALSO**

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

**COLOPHON**

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