Re: GNU make troubleshooting

[Alejandro Colomar]

Hi Dmitry!

On 2023-07-15 17:28, Dmitry Goncharov wrote:
[...]

> 
> $ make -d |tail +7 |head
> Reading makefiles...
> Reading makefile 'makefile'...
> Updating makefiles....
>  Considering target file 'makefile'.
>   Looking for an implicit rule for 'makefile'.
>    Trying pattern rule '%: %.o' with stem 'makefile'.
>    Trying implicit prerequisite 'makefile.o'.
>    Not found 'makefile.o'.
>    Trying pattern rule '%: %.c' with stem 'makefile'.
>    Trying implicit prerequisite 'makefile.c'.
> $
> 
> Upon startup make looks for a rule to update the makefile. (see How
> Makefiles Are Remade). This is what the initial portion of this debug
> output is about. If we don’t need your makefile to be remade, we can
> instruct make to skip this update process.
> 
> $ cat makefile
> all: hello
> makefile::;
> $ make -d |tail +7 |wc
>     730    4101   32848
> 
> Note, we added rule
> 
> makefile::;
> 
> This addition cut the debug output from 1338 to 730 lines.

Wow!  That's a great help for debugging the Linux man-pages's makefiles,
which don't need to be remade.  It was very painful to me to ignore so
much make -d output.  I applied the following patch, and it works like
a charm.

<https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/commit/?id=c98d237c22e9e898ae7d05e2222e7eac47791bd3>

Thanks a lot!
Alex

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