the GAsyncResult that was provided to the callback
a gsize to get the length of the data read in
a string with the data that was read before encountering any of the stop characters. Set length to a gsize to get the length of the string. This function will return NULL on an error.
GException on failure.
2.24
Finish an asynchronous call started by DataInputStream.readUptoAsync.
Note that this function does not consume the stop character. You have to use DataInputStream.readByte to get it before calling DataInputStream.readUptoAsync again.
The returned string will always be nul-terminated on success.