Sorry I misread your original post. I thought you tried to code your program to use syslog’s LOG_FTP facility.
Back to your question, LOG_FTP is a non standard facility and not all Unix/version supports it. If you check the QNX 6.1 ftpd document, you will see LOG_FTP is not mentioned, but QNX 6.2.1 ftpd document does mention it. I think it is a documen error. Or maybe QNX planned to support it in QNX 6.2.0 but dumped the idea in the actual release, which leaves an inacurate document.