File: gpgme.info,  Node: Error Sources,  Next: Error Codes,  Prev: Error Values,  Up: Error Handling

5.2 Error Sources
=================

The library ‘libgpg-error’ defines an error source for every component
of the GnuPG system.  The error source part of an error value is not
well defined.  As such it is mainly useful to improve the diagnostic
error message for the user.

   If the error code part of an error value is ‘0’, the whole error
value will be ‘0’.  In this case the error source part is of course
‘GPG_ERR_SOURCE_UNKNOWN’.

   The list of error sources that might occur in applications using
GPGME is:

‘GPG_ERR_SOURCE_UNKNOWN’
     The error source is not known.  The value of this error source is
     ‘0’.

‘GPG_ERR_SOURCE_GPGME’
     The error source is GPGME itself.  This is the default for errors
     that occur in the GPGME library.

‘GPG_ERR_SOURCE_GPG’
     The error source is GnuPG, which is the crypto engine used for the
     OpenPGP protocol.

‘GPG_ERR_SOURCE_GPGSM’
     The error source is GPGSM, which is the crypto engine used for the
     CMS protocol.

‘GPG_ERR_SOURCE_GCRYPT’
     The error source is ‘libgcrypt’, which is used by crypto engines to
     perform cryptographic operations.

‘GPG_ERR_SOURCE_GPGAGENT’
     The error source is ‘gpg-agent’, which is used by crypto engines to
     perform operations with the secret key.

‘GPG_ERR_SOURCE_PINENTRY’
     The error source is ‘pinentry’, which is used by ‘gpg-agent’ to
     query the passphrase to unlock a secret key.

‘GPG_ERR_SOURCE_SCD’
     The error source is the SmartCard Daemon, which is used by
     ‘gpg-agent’ to delegate operations with the secret key to a
     SmartCard.

‘GPG_ERR_SOURCE_KEYBOX’
     The error source is ‘libkbx’, a library used by the crypto engines
     to manage local keyrings.

‘GPG_ERR_SOURCE_USER_1’
‘GPG_ERR_SOURCE_USER_2’
‘GPG_ERR_SOURCE_USER_3’
‘GPG_ERR_SOURCE_USER_4’
     These error sources are not used by any GnuPG component and can be
     used by other software.  For example, applications using GPGME can
     use them to mark error values coming from callback handlers.  Thus
     ‘GPG_ERR_SOURCE_USER_1’ is the default for errors created with
     ‘gpgme_error’ and ‘gpgme_error_from_errno’, unless you define
     ‘GPGME_ERR_SOURCE_DEFAULT’ before including ‘gpgme.h’.