int strncasecmp(const char *s1,
const char *s2,
size_t n);
strncasecmp compares not more than n characters from the array pointed to by s1 to the array pointed to by s2 ignoring differences in case. Characters that follow a null character are not compared.
strncasecmp returns an integer greater than, equal to, or less than zero, if the possibly null-terminated array pointed to by s1 is greater than, equal to, or less than the possibly null-terminated array pointed to by s2.
strncasecmp conforms to POSIX.1-2008.