This function implements a comparison algorithm that orders alphanumeric strings in the way a human being would. The behaviour of this function is similar to strnatcmp(), except that the comparison is not case sensitive. For more infomation see: Martin Pool's Natural Order String Comparison page.
Similar to other string comparison functions, this one returns < 0 if str1 is less than str2; > 0 if str1 is greater than str2, and 0 if they are equal.
See also ereg(), strcasecmp(), substr(), stristr(), strcmp(), strncmp(), strncasecmp(), strnatcmp(), and strstr().