Compares two objects, byte by byte. The compare operation starts
    with the first byte in each object.

    Format

      #include  <string.h>

      int memcmp  (const void *s1, const void *s2, size_t size);

1 - Arguments

 s1

    A pointer to the first object.

 s2

    A pointer to the second object.

 size

    The length of the objects to be compared.

    If size is zero, the two objects are considered equal.

2 - Description

    The memcmp function uses native byte comparison. The sign of
    the value returned is determined by the sign of the difference
    between the values of the first pair of unlike bytes in the
    objects being compared. Unlike the strcmp function, the memcmp
    function does not stop when a null character is encountered.

3 - Return Value

    x                  An integer less than, equal to, or greater
                       than 0, depending on whether the lexical value
                       of the first object is less than, equal to, or
                       greater than that of the second object.