[dpdk-users] Build on Windows not working: "ERROR: Program 'echo' not found"

[Richardson, Bruce]

+Luca who also helped with getting docs building

> -----Original Message-----
> From: Dmitry Kozlyuk <dmitry.kozliuk at gmail.com>
> Sent: Wednesday, June 30, 2021 10:28 AM
> To: Rob Scheepens <rob.scheepens at nutanix.com>
> Cc: users at dpdk.org; Richardson, Bruce <bruce.richardson at intel.com>
> Subject: Re: [dpdk-users] Build on Windows not working: "ERROR: Program
> 'echo' not found"
> 
> 2021-06-30 08:41 (UTC+0000), Rob Scheepens:
> > Hello Dmitry,
> >
> > That works, thanks!
> >
> > Is there an issue open for this? If not, should I create one?
> 
> Not yet and I'm not sure is it Meson or DPDK issue.
> Meson's behavior changed between 0.57 and 0.58.1
> seemingly due to another feature added, on the other hand,
> DPDK code didn't work on Windows as expected.
> 
> +Bruce, build system maintainer.
> I think we'll sort this out, thank you for reporting the bug.
> 
> Bruce, in doc/meson.build, we have this:
> 
> doc_targets = []
> doc_target_names = []
> subdir('api')
> subdir('guides')
> 
> if doc_targets.length() == 0
>     message = 'No docs targets found'
> else
>     message = 'Building docs:'
> endif
> run_target('doc', command: ['echo', message, doc_target_names],
>     depends: doc_targets)
> 
> First, why there's no early exit if enable_docs=false?
> 

Looking through the code, I believe things are done this way so that, if we have the dependencies of sphinx and doxygen, you can do "ninja doc" to build the documentation even if "enable_docs" is set to false. We always have a valid "doc" target, irrespective of that setting, which controls only whether the docs are built as part of a regular build or not.

Regards,
/Bruce