Re: [Discuss-gnuradio] Passing file descriptors via SWIG

[Eric Blossom]

On Fri, Mar 13, 2009 at 01:49:31PM +0100, Martin Braun wrote:
> Hi,
> 
> following
> http://lists.gnu.org/archive/html/discuss-gnuradio/2009-02/msg00400.html,
> I tried connecting two processes with a FIFO using gr.file_descriptor_*.
> 
> However, I can't seem to pass the file descriptor from the Python to the
> C++ domain. This is the error message I get:
> 
> gr_file_descriptor_sink: Bad file descriptor
>
> This is the code (pipe1 was created by using 'mkfifo pipe1'):

The python file object, fid, is going out of scope, and thus the
underlying file is being closed.  Try self.fid = open(...)

Eric


> Source-File:
> 
> <<< SNIP >>>
> from gnuradio import gr
> class sig_source(gr.top_block):
>     def __init__(self):
>         gr.top_block.__init__(self)
> 
>         src = gr.sig_source_f(8000, gr.GR_SIN_WAVE, 2000, 1.0)
>         head = gr.head(gr.sizeof_float, 8000)
> 
>         print "Opening pipe..."
>         fid = open('pipe1', 'wb')
>         print "Done. fileno: ", fid.fileno()
>         sink = gr.file_descriptor_sink(gr.sizeof_float, fid.fileno())
> 
>         self.connect(src, head, sink)
> 
> if __name__ == '__main__':
>     try:
>         sig_source().run()
>     except KeyboardInterrupt:
>         pass