# Flags / xml to supress Add throttle warning?

**URL:** <https://www.ruby-forum.com/t/flags-xml-to-supress-add-throttle-warning/243138>\
**Category:** GNU Radio\
**Created:** [August 25, 2015, 5:28am UTC](https://www.ruby-forum.com/t/flags-xml-to-supress-add-throttle-warning/243138 "2015-08-25T05:28:31Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Sadaf\_N](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/858c86/32.png) [@Sadaf\_N](https://www.ruby-forum.com/u/Sadaf_N)\
**Post date:** [August 25, 2015, 5:28am UTC](https://www.ruby-forum.com/t/flags-xml-to-supress-add-throttle-warning/243138/1 "2015-08-25T05:28:31Z")

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I’ve built an OOT for some physical SDR hardware.  
However, when compiling a flowgraph in gnruradio-companion  
it prints a warning message about no audio or rf sink, so please  
insert a throttle.

Since my module actually paces the samples in hardware, I don’t  
want a throttle. How can I supress the warning message?

Looking through some GRC blocks, I’ve found two tags:

1

and another is

throttle

Reading the documentation that discusses XML tags in the block,  
[http://gnuradio.org/redmine/projects/gnuradio/wiki/GNURadioCompanion#Creating-the-XML-Block-Definition](http://gnuradio.org/redmine/projects/gnuradio/wiki/GNURadioCompanion#Creating-the-XML-Block-Definition)  
it doesn’t mention these tags, or what they do. Is one of these the  
correct way to suppress the flowgraph compile warning?

– Tom, N5EG

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**Author:** ![Tom\_McDermott](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/9fc29f/32.png) [@Tom\_McDermott](https://www.ruby-forum.com/u/Tom_McDermott)\
**Post date:** [August 25, 2015, 6:01am UTC](https://www.ruby-forum.com/t/flags-xml-to-supress-add-throttle-warning/243138/2 "2015-08-25T06:01:14Z")

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On 08/24/2015 11:26 PM, Tom McDermott wrote:

> 1  
> – Tom, N5EG
> 
> * * *
> 
> Discuss-gnuradio mailing list  
> [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
> [Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio)  
> I think the newer way is to use throttle

But for backwards compat, you can use 1

It’s an indicator to GRC that this block provides a flow-regulated data  
stream.

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**Author:** ![Tom\_McDermott](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/9fc29f/32.png) [@Tom\_McDermott](https://www.ruby-forum.com/u/Tom_McDermott)\
**Post date:** [August 25, 2015, 6:18am UTC](https://www.ruby-forum.com/t/flags-xml-to-supress-add-throttle-warning/243138/3 "2015-08-25T06:18:45Z")

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Thanks. throttle it will be … (works fine).

– Tom, N5EG