This is a proof-of-concept module and might not work well in some environments (such as a graphical login manager). I have only tested it against text mode unix login (shadow).
Be aware that libfprint does not guarantee a stable ABI. So, pam_fprint may break if you upgrade libfprint in future without recompiling pam_fprint.
You must enroll a finger before you can use pam_fprint. Currently the only easy way to do this is to use the
enroll example from libfprint.