Hi Michael, okay, final mail on this issue today: On Tue, 6 Sep 2016, Johannes Schindelin wrote: > Your original issue seemed to be that the gpg command could succeed, but > still no signature be seen. There *must* be a way to test whether the > called program added a signature, simply by testing whether *any* > characters were written. > > And if characters were written that were not actually a GPG signature, > maybe the enterprisey user who configured the gpg command to be her magic > script actually meant something else than a GPG signature to be added? I actually just saw that this is *precisely* what the code does already: if (ret || signature->len == bottom) return error(_("gpg failed to sign the data")); Why is this not good enough? Ciao, Dscho