File: gpgme.info,  Node: Error Handling,  Next: Exchanging Data,  Prev: Algorithms,  Up: Top

5 Error Handling
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Many functions in GPGME can return an error if they fail.  For this
reason, the application should always catch the error condition and take
appropriate measures, for example by releasing the resources and passing
the error up to the caller, or by displaying a descriptive message to
the user and cancelling the operation.

   Some error values do not indicate a system error or an error in the
operation, but the result of an operation that failed properly.  For
example, if you try to decrypt a tempered message, the decryption will
fail.  Another error value actually means that the end of a data buffer
or list has been reached.  The following descriptions explain for many
error codes what they mean usually.  Some error values have specific
meanings if returned by a certain functions.  Such cases are described
in the documentation of those functions.

   GPGME uses the ‘libgpg-error’ library.  This allows to share the
error codes with other components of the GnuPG system, and thus pass
error values transparently from the crypto engine, or some helper
application of the crypto engine, to the user.  This way no information
is lost.  As a consequence, GPGME does not use its own identifiers for
error codes, but uses those provided by ‘libgpg-error’.  They usually
start with ‘GPG_ERR_’.

   However, GPGME does provide aliases for the functions defined in
libgpg-error, which might be preferred for name space consistency.

* Menu:

* Error Values::                  The error value and what it means.
* Error Sources::                 A list of important error sources.
* Error Codes::                   A list of important error codes.
* Error Strings::                 How to get a descriptive string from a value.