GCR is a library for displaying certificates, and crypto UI, accessing
key stores. It also provides the viewer for crypto files on the GNOME
desktop.

GCK is a library for accessing PKCS#11 modules like smart cards, in a
(G)object oriented way.


DEBUG TRACING
==============

The Gcr and Gck libraries contain statements which help debug flow
and logic. In many cases these help you track down problems.

Use the environment variable GCR_DEBUG='all' or GCR_HELP='xxx' to
display either all messages or a specific category of debug messages.
To figure out what you can use in place of the 'xxx' category above,
use GCR_DEBUG='help' and you'll see a list of all the messages.

Example to display all debug messages:

$ GCR_DEBUG=all gcr-viewer /path/to/certificate.crt
(gcr-viewer:9418): Gcr-DEBUG: gcr_pkcs11_initialize_async: starting initialize of registered modules
...

Example to display the various debug categories:

$ GCR_DEBUG=help gcr-viewer /path/to/certificate.crt
Supported debug values: library certificate-chain parse gnupg trust import key prompt all help

Example to display debug messages for a specific category:

$ GCR_DEBUG=library gcr-viewer /path/to/certificate.crt
(gcr-viewer:9503): Gcr-DEBUG: gcr_pkcs11_initialize_async: starting initialize of registered modules
...

If you wish to permanently enable certain debug messages, include compiler
directives like this when configuring this library:

$ CFLAGS='-DGCR_DEBUG=library' ./configure ...

For the Gck debug messages simply replace 'GCR_DEBUG' with 'GCK_DEBUG'
in the above examples.