On Wed, Apr 03, 2024 at 10:55:26AM +0100, Graham Leggett wrote:
Hi all,
Looking back in time to the definitions of ldap_get_values() and ldap_get_values_len(), we are told that "If the attribute values are binary in nature, and thus not suitable to be returned as an array of char *'s, the ldap_get_values_len() routine can be used instead."
This has been historically vague - first off, what happens if an attempt is made to call ldap_get_values() on binary data, do you get an error, or garbage data? The source isn't giving me a clear answer.
Hi Graham, in this case binary data means embedded NULs (\0) can be found: given that what you get back is a naive char * for each value, you stand to lose information about whether that NUL is part of the value or a string terminator.
Second question is how do you know which of ldap_get_values() or ldap_get_values_len() to call? Obviously you can manually know this, but I'm interested in automated behaviour. What is the canonical way to discover that if you queried a jpegPhoto (for example) that the result would be binary?
You either expect the data to be a string of some sort (no embedded NULs), then you're free to use whichever or you are prepared to accept arbitrary bytestreams and you need to use the one that returns bervals. That's all there is.
You're welcome to propose better wording if you can make it clearer to a reasonably competent C developer (I'm sure we can assume that they understand how strings are laid out etc.)
Regards,