Loads a signature from the signature file for this, which is given by get_file.
The signature contents are placed in contents, and length is set to the size of the contents
string. The contents string should be freed with g_free when no
longer needed.
If the signature file is executable, it will be executed and its output captured as the email signature content. If the signature file is not executable, the email signature content is read directly from the file.
| this |
an Source |
| contents |
return location for the signature content |
| length |
return location for the length of the signature content, or null if the length is not needed |
| cancellable |
optional Cancellable object, or null |
|
true on success, false on failure |