Hi Xianda, the io_signature specifies a minimum and a maximum number of inputs, so this might be 1,2 or 3.
Greetings, Marcus On 04.06.2014 10:24, xianda wrote: > Hi: > Thank you so much. > Now i want to ask:if we set > gr::block("c_vcvc", > > gr::io_signature::make(1, 3, sizeof(gr_complex)*length1), > > gr::io_signature::make(1, 1, sizeof(gr_complex)*length1)) > then: ninput_items_required.size ()=1 or 3? > Thanks, > Best regards > > > > > > At 2014-06-04 03:10:40, "Marcus Müller" <marcus.muel...@ettus.com> wrote: > Hi Xianda, > > Easiest answer first: > > 2. You need to write a forecast if, and only if, you're using general_work. I > generally try to avoid doing that. > > Then: > 1. > ninput_items_required is, as you can see in the function signature, a > reference to a vector. > The size of the vector is the number of input ports. > Compare to > http://gnuradio.org/doc/doxygen/classgr_1_1block.html#a5bc118d94944d2ff71e378f807fb8d28 > > Greetings, > Marcus > > > On 04.06.2014 08:22, xianda wrote: > > Hi all: > I want to know something about the forecast(). > I have already known that forcast() can tell scheduler how many > input items are required for each output item. > 1.But now i have read two example: > The first one: > void your_block::forecast(int > noutput_items,gr_vector_int &ninput_items_required){ > ninput_items_required[0]=100 * > noutput_items; > > ninput_items_required[1]=100 * > noutput_items; } > I have already understand it. > But the second one: > void forecast (int noutput_items, gr_vector_int > &ninput_items_required) > { > unsigned ninputs = ninput_items_required.size > (); > for (unsigned i = 0; i < ninputs; i++) > ninput_items_required[i] = 1;} > I can't understand since we can't know how many input > items we required,why use ninput_items_required.size ().Can someone help me? > 2.I want to know if we use the general_work().Is it means that > we must use the forcast()?Thanks. > Best regards > > > > > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.orghttps://lists.gnu.org/mailman/listinfo/discuss-gnuradio > _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio