Re: [Discuss-gnuradio] Correct usage of gr::io_signature::makev

[Marcus Müller]

Ah, I got that wrong,

The difference is that fll_band_edge_cc_impl.cc doesn't declare that
static variable as class member, but you do – that leads to a problem,
because that way, the C++ type sync_short_impl as defined in your
_impl.cc differs from the one in the _impl.h, but requires that an
object be allocated in memory before the first instance of that type
can be allocated. Therefore, in-class defined static members can only
be integral types. (And if you didn't understand much of that, don't
worry, it only happened to cross my horizon because I introduced a
strange bug when I tried to fix PMT usage in GNU Radio, and had to go
back, understand a static initialization problem, which took hours, and
fix my changes.)

Workaround: don't make ios and iosig a part of the class, but only of
the gr::ieee802_11 namespace (and maybe give them more unique names
when doing so).

Best regards,
Marcus

On Sat, 2018-04-28 at 17:39 +0200, Sumit Kumar wrote:
> Hi Marcus,
> 
> Actually I din't do that since the reference code which I was
> following, 
> i.e.,
> 
> fll_band_edge_cc_impl.cc, has no such declaration in the
> corresponding 
> header fll_band_edge_cc_impl.h
> 
> Sumit
> 
> On 28/04/2018 17:28, Marcus Müller wrote:
> > Hi Sumit,
> > 
> > I don't see where `ios` is being declared constantly and/or
> > statically
> > before line 31? Does that happen in the header?
> > 
> > Best regards,
> > Marcus
> > On Sat, 2018-04-28 at 16:51 +0200, Sumit Kumar wrote:
> > > Hi,
> > > In order to look for correct usage of gr::io_signature::makev, I
> > > checked this example https://github.com/gnuradio/gnuradio/blob/ma
> > > ster
> > > /gr-digital/lib/fll_band_edge_cc_impl.cc
> > > and found
> > > static int ios[] = {sizeof(gr_complex), sizeof(gr_complex),
> > > sizeof(gr_complex), sizeof(float)};
> > > static std::vector<int> iosig(ios, ios+sizeof(ios)/sizeof(int));
> > > and then use as io_signature::makev(1, 4, iosig))
> > > Basically I have to use it in sync_short.cc from gr-ieee 80211 in
> > > order to create more inputs.
> > > But if I use the above two lines inside the class i.e.
> > > sync_short_impl, I get lots of error. I have attached the file
> > > for
> > > reference. Could you please suggest me correct usage. I can give
> > > more
> > > information if needed.
> > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > > ~~~~
> > > ~~~~~~~
> > > /home/john/myprefix/src/gr-ieee-80211/lib/sync_short.cc:31:84:
> > > error:
> > > in-class initialization of static data member ‘int
> > > sync_short_impl::ios []’ of incomplete type
> > >   tic int ios[] = {sizeof(gr_complex), sizeof(float),
> > > sizeof(float),
> > > sizeof(float)};
> > >                                                                  
> > >      
> > >              ^
> > > /home/john/myprefix/src/gr-ieee-80211/lib/sync_short.cc:32:31:
> > > error:
> > > ‘ios’ is not a type
> > >   static std::vector<int> iosig(ios,
> > > ios+sizeof(ios)/sizeof(int));
> > >                                 ^
> > > /home/john/myprefix/src/gr-ieee-80211/lib/sync_short.cc:32:36:
> > > error:
> > > ‘ios’ is not a type
> > >   static std::vector<int> iosig(ios,
> > > ios+sizeof(ios)/sizeof(int));
> > >                                      ^
> > > /home/john/myprefix/src/gr-ieee-80211/lib/sync_short.cc:32:39:
> > > error:
> > > expected ‘,’ or ‘...’ before ‘+’ token
> > >   static std::vector<int> iosig(ios,
> > > ios+sizeof(ios)/sizeof(int));
> > >                                         ^
> > > /home/john/myprefix/src/gr-ieee-80211/lib/sync_short.cc: In
> > > constructor ‘sync_short_impl::sync_short_impl(double, unsigned
> > > int,
> > > bool, bool)’:
> > > /home/john/myprefix/src/gr-ieee-80211/lib/sync_short.cc:35:39:
> > > error:
> > > no matching function for call to ‘gr::io_signature::makev(int,
> > > int,
> > > std::vector<int> (&)(int, int))’
> > >      gr::io_signature::makev(4, 4, iosig),
> > >                                         ^
> > > In file included from
> > > /home/john/myprefix/include/gnuradio/basic_block.h:30:0,
> > >                   from
> > > /home/john/myprefix/include/gnuradio/block.h:27,
> > >                   from /home/john/myprefix/src/gr-ieee-
> > > 80211/include/ieee802-11/sync_short.h:21,
> > >                   from /home/john/myprefix/src/gr-ieee-
> > > 80211/lib/sync_short.cc:17:
> > > /home/john/myprefix/include/gnuradio/io_signature.h:100:17: note:
> > > candidate: static gr::io_signature::sptr
> > > gr::io_signature::makev(int,
> > > int, const std::vector<int>&)
> > >       static sptr makev(int min_streams, int max_streams,
> > >                   ^
> > > /home/john/myprefix/include/gnuradio/io_signature.h:100:17: note:
> > > no known conversion for argument 3 from ‘std::vector<int>(int,
> > > int)’
> > > to ‘const std::vector<int>&’
> > > lib/CMakeFiles/gnuradio-ieee802_11.dir/build.make:584: recipe for
> > > target 'lib/CMakeFiles/gnuradio-ieee802_11.dir/sync_short.cc.o'
> > > failed
> > > make[2]: *** [lib/CMakeFiles/gnuradio-
> > > ieee802_11.dir/sync_short.cc.o]
> > > Error 1
> > > CMakeFiles/Makefile2:200: recipe for target
> > > 'lib/CMakeFiles/gnuradio-
> > > ieee802_11.dir/all' failed
> > > make[1]: *** [lib/CMakeFiles/gnuradio-ieee802_11.dir/all] Error 2
> > > Makefile:138: recipe for target 'all' failed
> > > make: *** [all] Error 2
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> 
>