Re: [Discuss-gnuradio] Question: How to read file contents

[George Nychis]

Hi Jason,

Jason Anders wrote:
> Hi!
>
> Since no one has responded to my post regarding my problem on reading a 
> file. I will post another message regarding this. But instead, I'll ask 
> a very basic question.

I think it's because your post is a little unclear.

When you say "I have a problem reading an ascii file" ...is it binary 
float data?  Is it string representation of numbers?  It makes a big 
difference.  When you say "ascii" I interpret this as "12.5" in text 
format which is not what gr.file_source is going to parse.

> How do you read contents from a file using GNU Radio blocks? I always 
> get an empty list when I try to run the code that I posted here like 5 
> days ago......

It all depends what is in this file, as I stated before.  Your code is 
attempting to read a binary file of floats:
yrx1_real = gr.file_source(gr.sizeof_float,{file location},FALSE)

is it really a binary file of floats?  or is it:
12.7
234.5
... etc

Aside from that, you never actually start your flow graph.  I've never 
used wait(), but I'm pretty sure you still need to fg.start() ... 
otherwise it never starts and you never ever get data in what you're 
trying to read.  It's always going to be whatever it's initialized as.

> P.S.
>
> I really wish GNU Radio has a better user manual just like MATLAB. I 
> mean, I posted a very basic question and I'm expecting answers by now.

GNU Radio is open source, unlike MATLAB.  That means you literally have 
everything documented in code.  If you're not sure how a block works, 
you just look at the code.  Search the mailing list for some of Firas' 
posts about the documentation he is generating.  Here's a small guide I 
found from google:
http://www.nd.edu/~jnl/sdr/docs/tutorials/9.html

The code always evolves, it's hard to keep manuals up to date, which is 
why the code itself is usually the best documentation :)

- George