Re: svn commit: r1917094 [2/3] - in /apr/apr/trunk: ./ build/ docs/ include/ include/private/ ldap/ misc/unix/ test/

On 20 Mar 2025, at 16:56, Ruediger Pluem <[email protected]> wrote:

>> This code is compiled with openldap and ldap_connect does not seem to be present with openldap at least not with 2.4.46 which is
>> delivered with RedHat 8. I can see it though in openldap 2.6.6 which is delivered with RedHat 9
>> 
>> ldap/apr_ldap.c: In function ‘apr__ldap_connect’:
>> ldap/apr_ldap.c:1091:15: warning: implicit declaration of function ‘ldap_connect’; did you mean ‘ldap_cancel’?
>> [-Wimplicit-function-declaration]
>>     err->rc = ldap_connect(ld);
>>               ^~~~~~~~~~~~
>>               ldap_cancel
> 
> Thanks to r1924295 this compiles now, but it creates just a stub for apr_ldap_connect that always returns APR_ENOTIMPL.
> As apr_ldap_connect is a central function of the new API I think it would be better to fail during configure time
> if ldap_connect is not found instead of creating a binary with an unusable API. Maybe a check for an appropriate version
> of openldap (>= 2.5 looks like to be fine) in case openldap is the library being used would be also helpful to give the
> user compiling the code a better hint what is required to make the API work.

I encountered a missing ldap_connect() on the ancient openldap that ships with latest MacOS. While ldap_connect() is present on Windows and reasonably modern openldap, ldap_connect() is missing on IBM Tivoli, meaning there would be no way to ever support these platforms in future.

ldap_connect() is marked as optional in the APIs that support it, the point is have a clear location where you can catch and return connect errors, instead of encountering them in a search or a modify. If the function is not there, it is not the end of the world.

The test case handles a possibly missing ldap_connect like this:

https://github.com/apache/apr/blob/trunk/test/testldap.c#L991

I think the best approach is to let the caller decide if they care or not. If you care, you might get APR_ENOTIMPL and can respond accordingly (fail, work around). If you don't care, you don't use ldap_connect() at all. The API presents the underlying reality to you, and you get to decide what to do.

Regards,
Graham
--