Re: [Discuss-gnuradio] Message passing as input and output in block (C++ coding)

[Josh Blum]

> I generated the BLOB_METADATA as pmt::pmt_t type. However, I cannot post
> blob_data because is related to _msg (in the previous example), which is a
> gr_tag_t type.
> 

There are two post_msg methods. The key/value version of the method is a
convenience method that makes a gr_tag_t and sets key and value

https://github.com/guruofquality/grextras/blob/master/include/gnuradio/block.h#L208

> If a copy this blob for example to a new blob as you suggested previously,
> can I then post using: this->post_msg(0, BLOB_METADATA,blob_data, _id); ?.
> I mean, will it change to pmt_t type?.

The value parameter has to be type pmt::pmt_t

There is a function to create a blob from ptr and length:
http://gnuradio.org/cgit/gnuradio.git/tree/gruel/src/include/gruel/pmt.h#n330

-josh