Re: Makefiles guidance

[Bob Friesenhahn]

On Fri, 15 Jun 2018, Anmol Mishra wrote:

> https://pastebin.com/gDiMCEpC
>
> https://github.com/Shopify/pyoozie/blob/master/Makefile
>
> What actually is my_cmd.python.2 and my_cmd.python.3 really do.
> In these, What actually is happening in these lines?
>
>   1. python_version_full := $(wordlist 2,4,$(subst ., ,$(shell python
>   --version 2>&1)))
>   2. python_version_major := $(word 1,${python_version_full}

This is GNU make specific syntax (not portable) and so you should 
consult the GNU make manual.

As a quick check you can add something this at the bottom of the 
Makefile to see what these variables end up being defined to:

test_vars:
        echo $(python_version_full)
        echo $(python_version_major)

and then do

make test_vars

to see what gets printed.

Bob
--
Bob Friesenhahn
address@hidden, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/