PAM logging

I wrote my first custom PAM module for SSH multifactor authentication. My pam module uses the curllib c library to make http requests. The module executes but there are error that I need to debug related to the use of the curlib library. However I'm not able to log any errors from my module using stderror or even writing to a file using fopen. The var/log/secure doesn't provide enough detailed information or what is happening inside the application. How can I log stderror messages to a log from within my pam module?