How does uname work? How is version.h created?

[Milan Obuch <nu...@dino.sk>]

Hi,

as I am building NuttX from git repository, uname output is not that
helpful. See here:

nsh> uname -a
NuttX  0.0.0  Aug 16 2023 16:35:21 risc-v bl602evb

There is just one way to know something more - look at some file and
guess which one it is. Date/time shown here is that of the moment you
start build process. In directory with binaries, dates shown are that
of the finishing operation of the build process. If you are building
various binaries sequentially, it is possible to tell.

In FreeBSD, you get much more info with uname:

% uname -a
FreeBSD zybo.dino.sk 14.0-CURRENT FreeBSD 14.0-CURRENT #0 2022-08-01-2c4276aaa2d0: Fri Jul  7 22:06:48 CEST 2023 root@tiny.dino.sk:/usr/obj/usr/src/arm.armv7/sys/ZYNQ arm

Output varies, but I think it could help a bit if I can include more
info in version.h - I'd prefer including git hashes and configuration
used for build recorded here.

So the question - how is version.h being created? Even if this is not
included upstream, I can have it done at least locally, but being still
in starting phase, I need some pointer here...

Regards,
Milan

Re: How does uname work? How is version.h created?

[Gregory Nutt <sp...@gmail.com>]

> So the question - how is version.h being created? Even if this is not
> included upstream, I can have it done at least locally, but being still
> in starting phase, I need some pointer here...

It is created from .version by tools/mkversion under the control of 
tools/Unix.mk.  .version is created by tools/version.sh