In PHP what does it mean by a binary safe string comparison?

Question

Some examples of PHP functions that contain this description are strcmp () and strcasecmp (), how do they work internally? How does this binary comparison work? I have not been able to understand why these functions return -1, 0 and 1 (or <0, 0 and >0)

Thanks in advance

Answer 1

1. If the two strings have identical BEGINNING parts, they are truncated from both strings.
2. The resulting strings are compared with two possible outcomes:

• if one of the resulting strings is an empty string, then the length of the non-empty string is returned (the sign depending on the order in which you pass the arguments to the function)
• in any other case just the numerical values of the FIRST characters are compared. The result is +1 or -1 no matter how big is the difference between the numerical values.

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