2.2.15 int strcmp
int strcmp(const char *, const char *) __ATTR_PURE__
The strcmp() function compares the two strings s1 and s2.
Remember:
The strcmp() function returns an integer less than, equal to, or greater than zero if s1 is found, respectively, to be less than, to match, or be greater than s2. A consequence of the ordering used by strcmp() is that if s1 is an initial substring of s2, then s1 is considered to be "less than" s2.