[GSoC 2020]: Doubts in building RSB Recipe for EPICS for multiple architectures

[Chris Johns]

On 29/7/20 4:43 am, Mritunjay Sharma wrote:
> First of all apologies for a little late response, 
> please find the link to the blogs which tell how to Build EPICS7 with 
> RTEMS5 for pc-386 by hand here: 
> 
> Part 1
> : https://medium.com/@mritunjaysharma394/installing-rtems-ecosystem-and-building-your-first-bsp-993d1cf38902
> 
> Part
> 2: https://medium.com/@mritunjaysharma394/building-epics7-with-rtems5-by-hand-12d9fbd2eb82
> 
> Please do have a read and give me your feedback for improvements
> 

It looks good.

I think adding the commands you use after the text "Unzip the downloaded Zip
file inside this directory." helps. If the blob captures the exact commands it
makes it easier for me to follow. The EPICS link is hard to find.

> On Mon, Jul 27, 2020 at 7:20 AM Chris Johns <chrisj at rtems.org
> <mailto:chrisj at rtems.org>> wrote:
> 
>     On 27/7/20 10:34 am, Mritunjay Sharma wrote:
>     >
>     > Please find the patch for PC for EPICS here
>     >
>     https://github.com/mritunjaysharma394/epics-mritunjay/blob/master/patches/0001-Added-Support-for-RTEMS-pc386.patch
> 
>     Thanks.
> 
>     > As an experiment, in the 4 patches I have sent to devel for RSB recipe a few
>     > days pack, I worked on a local file. I will modify it to published source soon
>     > in the next version of patch.
> 
>     Are the EPICS configure files just Makefiles?
> 
> 
> I think so and more clarity can be given by Heinz on it.  

Lets assume they are for now.

>     Can the variables altered in your patch be controlled from the command line?
> 
>     What does the `T_A` variables in EPICS mean? I see this is used here ...
> 
> I searched about it in the EPICS documentation and found that T_A variable refers
> to 'T_A) is the current build’s target architecture'.

Target Architecture seems likely. I would assume we need to look into what these
are more.

> I tried to alter it using the command line but I think it didn't work or maybe I
> was doing in the wrong way? Heinz, can you comment on this? 

Please post the commands and the output. I find it hard to follow what is
happening here.
 
>     https://github.com/mritunjaysharma394/epics-mritunjay/blob/master/configure/CONFIG#L64
> 
>     If you look down from this there are some special includes ...
> 
>     https://github.com/mritunjaysharma394/epics-mritunjay/blob/master/configure/CONFIG#L113
> 
>     What are these files for?
> 
> 
> I found this information about them in the documentation: 
> 
> 'User specific override definitions are allowed in user created files in the user’s
> <home>/configure subdirectory. These override definitions will be used for builds
> in all <top> directory structures. The files must have the following names.
> 
> <home>/configure/CONFIG_USER
> <home>/configure/CONFIG_USER.<epics_host_arch>
> <home>/configure/CONFIG_USER.Common.<targetarch>
> <home>/configure/CONFIG_USER.<epics_host_arch>.<targetarch>'

That is promising but using $HOME makes it hard.

> The link to the documentation is: 
> https://epics.anl.gov/base/R3-15/6-docs/AppDevGuide/BuildFacility.html


Thank you for the link. I will take a look.

Chris