The strncmp() function shall compare not more than n bytes (bytes
that follow a null byte 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.
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy between
this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.opengroup.org/unix/online.html