const char* content_type,
Adds a content type to the application information to indicate the application is capable of opening files with the given content type.
The data is owned by the caller of the function. The value is a NUL terminated UTF-8 string.
The return location for a recoverable error.
The argument can be
If the return location is not
NULL, then you must initialize it to a
The argument will left initialized to
NULLby the method if there are no errors.
In case of error, the argument will be set to a newly allocated
GError; the caller will take ownership of the data, and be responsible for freeing it.