rld Manual

Using the rld Loader Library
RLD Manual—528857-006
2-13
dlerror()
The dlerror function returns a null pointer if you call it in either of these situations:

Before you call any other DLL function

Immediately after you call dlerror() itself (regardless of the value returned by
the previous call)
You can obtain the numeric form of the error by calling the dlresultcode() function.
You can call dlresultcode() immediately before or after calling dlerror().
Neither function affects the information returned by the other.
The dlerror() function does not set the errno variable.