gpgme_data_type_t type is used to return the detected type
of the content of a data buffer.
This is returned by
gpgme_data_identify if it was not possible
to identify the data. Reasons for this might be a non-seekable stream
or a memory problem. The value is 0.
The type of the data is not known.
The data is an OpenPGP signed message. This may be a binary signature, a detached one or a cleartext signature.
This is a generic OpenPGP message. In most cases this will be encrypted data.
This is an OpenPGP key (private or public).
This is a CMS signed message.
This is a CMS encrypted (enveloped data) message.
This is used for other CMS message types.
The data is a X.509 certificate
The data is a PKCS#12 message. This is commonly used to exchange private keys for X.509.
gpgme_data_identify returns the type of the data
with the handle dh. If it is not possible to perform the
identification, the function returns zero
GPGME_DATA_TYPE_INVALID). Note that depending on how the data
object has been created the identification may not be possible or the
data object may change its internal state (file pointer moved). For
file or memory based data object, the state should not change.