strcmp - compare two strings
int strcmp(const char *s1, const char *s2);
The strcmp() function compares the string pointed to by s1 to the string 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 completion, strcmp() returns an integer greater than, equal to or less than 0, if the string pointed to by s1 is greater than, equal to or less than the string pointed to by s2 respectively.
No errors are defined.
Derived from Issue 1 of the SVID.