All functions return a code of the Punycode_status enumerated type:
Punycode_status PUNYCODE_SUCCESS = 0
Successful operation. This value is guaranteed to always be zero, the
remaining ones are only guaranteed to hold non-zero values, for
logical comparison purposes.
Punycode_status PUNYCODE_BAD_INPUT
Input is invalid.
Punycode_status PUNYCODE_BIG_OUTPUT
Output would exceed the space provided.
Punycode_status PUNYCODE_OVERFLOW
Input needs wider integers to process.