All functions return a code of the Stringprep_rc enumerated type:
Stringprep_rc STRINGPREP_OK = 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.
Stringprep_rc STRINGPREP_CONTAINS_UNASSIGNED
String contain unassigned Unicode code points, which is forbidden by
the profile.
Stringprep_rc STRINGPREP_CONTAINS_PROHIBITED
String contain code points prohibited by the profile.
Stringprep_rc STRINGPREP_BIDI_BOTH_L_AND_RAL
String contain code points with conflicting bidirection category.
Stringprep_rc STRINGPREP_BIDI_LEADTRAIL_NOT_RAL
Leading and trailing character in string not of proper bidirectional
category.
Stringprep_rc STRINGPREP_BIDI_CONTAINS_PROHIBITED
Contains prohibited code points detected by bidirectional code.
Stringprep_rc STRINGPREP_TOO_SMALL_BUFFER
Buffer handed to function was too small. This usually indicate a
problem in the calling application.
Stringprep_rc STRINGPREP_PROFILE_ERROR
The stringprep profile was inconsistent. This usually indicate an
internal error in the library.
Stringprep_rc STRINGPREP_FLAG_ERROR
The supplied flag conflicted with profile. This usually indicate a
problem in the calling application.
Stringprep_rc STRINGPREP_UNKNOWN_PROFILE
The supplied profile name was not known to the library.
Stringprep_rc STRINGPREP_NFKC_FAILED
The Unicode NFKC operation failed. This usually indicate an internal
error in the library.
Stringprep_rc STRINGPREP_MALLOC_ERROR
The malloc was out of memory. This is usually a fatal error.