# Problem in creating an OOT module

**URL:** <https://www.ruby-forum.com/t/problem-in-creating-an-oot-module/234622>\
**Category:** GNU Radio\
**Created:** [March 18, 2015, 1:11am UTC](https://www.ruby-forum.com/t/problem-in-creating-an-oot-module/234622 "2015-03-18T01:11:55Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\
**Post date:** [March 18, 2015, 1:11am UTC](https://www.ruby-forum.com/t/problem-in-creating-an-oot-module/234622/1 "2015-03-18T01:11:55Z")

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Hello everyone,

I was wondering if anyone can help me with a small issue. I want to use  
the  
tagged\_file\_sink block in gnuradio companion, but with a couple of  
additional features suitable for my application needs. So I decide to  
create an OOT module, and as a start simply copy-pasted the original  
code  
for the tagged\_file\_sink (adjusting the name of the block of course)  
just  
to see if it works before I start editing it with my own adjustments.  
But I  
get a compilation error when I use the make command.

The errors are something like: tagged\_file\_sink\_v2\_impl.cc: error:  
‘perror’  
was not declared in this scope  
perror(filename.str().c\_str());

The rest of the errors I’m getting are similar to this: “‘something’ was  
not declared in this scope.”

Up till now I’ve only used gnuradio companion, never got to delve into  
actual coding or making my own blocks, so more of a beginner in this  
area,  
and I’m pretty sure that I’m missing something very basic, so I hope  
someone can help me figure this out.

Thank you,

Best,  
Ali

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**Author:** ![alirose](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/bc79bd/32.png) [@alirose](https://www.ruby-forum.com/u/alirose)\
**Post date:** [March 18, 2015, 1:22am UTC](https://www.ruby-forum.com/t/problem-in-creating-an-oot-module/234622/2 "2015-03-18T01:22:48Z")

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On Tue, Mar 17, 2015 at 8:10 PM, Ali R. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> The errors are something like: tagged\_file\_sink\_v2\_impl.cc: error:
> 
> Thank you,
> 
> Best,  
> Ali

This is basically a C/C++ question, not GNU Radio. You’re missing  
include  
files in your code. For instance, take a look at:

$ man 3 perror

It tells you that it needs “#include \<stdio.h\>”. You’ll find similar  
things  
for the other errors your having.

Tom

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**Author:** ![alirose](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/bc79bd/32.png) [@alirose](https://www.ruby-forum.com/u/alirose)\
**Post date:** [March 18, 2015, 1:37am UTC](https://www.ruby-forum.com/t/problem-in-creating-an-oot-module/234622/3 "2015-03-18T01:37:50Z")

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Well, it was definitely something simple 🙂 Thank you for your help Tom!

Best,  
Ali