int strncmp(const char *s1, const char *s2, size_t n);
IEEE Std 1003.1-2017
strncmp() function shall compare not more than n bytes (bytes that follow a NUL character are not compared)
from the array pointed to by s1 to the array pointed to by s2.
The sign of a non-zero return value is determined by the sign of the difference between the values of the first pair of bytes
(both interpreted as type
unsigned char) that differ in the strings being compared.
Upon successful completion,
strncmp() shall return an integer greater than, equal to, or less than
0, 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 respectively.
No errors are defined.