GpgmePassphraseCb: no way to make difference between cancel and invalid password

[Stéphane Corthésy]

Hi,

Using gpgme 0.3.8:
When using a context to sign or decrypt data, according to the operation 
result (the GpgmeError value) there is no way to make the difference 
between the two following situations:
1) User typed 3 times an invalid passphrase
2) User cancelled operation (GpgmePassphraseCb returned NULL)
In both cases the operation result is GPGME_No_Passphrase.

Is this the expected behavior? Shouldn't we get a different operation 
result when user cancelled operation?

Stéphane