May 26, 2018
Compare version strings as in sort –version-sort
Compare version strings
This function compares strings S1 and S2
By PREFIX in the same way as strcmp. Then by VERSION most similarly to version compare of Debian's dpkg. Leading zeros in version numbers are ignored. If both PREFIX and VERSION are equal, strcmp function is used for comparison. So this function can return 0 if and only if strings S1 and S2 are identical.
It returns number >0 for S1 > S2, 0 for S1 == S2 and number <0 for S1 < S2.