2013-03-01 07:37:46

by justin

[permalink] [raw]
Subject: Re: [PATCH 2/2] kconfig: use config scripts to detect ncurses libs

On 28/02/13 22:50, Sven Joachim wrote:
> On 2013-02-28 10:59 +0100, [email protected] wrote:
>
>> Ncurses provides a config script (ncurses5-config) to assist finding ncurses.
>> This patch makes use of it to detect the necessary libs for linking of the
>> ncurses nconfig dialog.
>
> That script is not necessarily called ncurses5-config, it might also be
> called ncurses6-config is ncurses is configured for a different ABI
> (--enable-ext-colors, --enable-ext-mouse). Although I would suspect
> that any distribution who does that provides a compatibility symlink.
>

We don't do that, but I rechecked with building ncurses manually. You
are right. How widely spread is the usage of this options? Or is it
rather an experimental option?
What we could do is simple extending the syntax to additionally check
for the ABI version 6 config scripts. Is this an option to consider?

>> scripts/kconfig/Makefile | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile
>> index 3091794..c372976 100644
>> --- a/scripts/kconfig/Makefile
>> +++ b/scripts/kconfig/Makefile
>> @@ -216,7 +216,9 @@ HOSTCFLAGS_gconf.o = `pkg-config --cflags gtk+-2.0 gmodule-2.0 libglade-2.0` \
>>
>> HOSTLOADLIBES_mconf = $(shell $(CONFIG_SHELL) $(check-lxdialog) -ldflags $(HOSTCC))
>>
>> -HOSTLOADLIBES_nconf = -lmenu -lpanel -lncurses
>> +HOSTLOADLIBES_nconf = -lmenu -lpanel
>> +HOSTLOADLIBES_nconf += $(shell ncursesw5-config --libs 2>/dev/null \
>> + || ncurses5-config --libs 2>/dev/null )
>
> This will link with ncursesw, not ncurses. Probably not what you want,
> since nconf.h does not #include the right headers for that.
>

That's true, and again it would change two things at once. I will go
back to simple -lncurses as it was before.

> On Debian/Ubuntu, there's also the problem that ncursesw5-config exists
> even if the libncursesw5-dev package is not installed, so this patch
> makes the build fail in such cases.

Will be solved when reverting as described above. But actually it smells
like a bug in the package management, doesn't it? Why are build time
config scripts shipped in runtime only packages? What is their purpose?

>
> Can we just call ncurses5-config and not ncursesw5-config, or are there
> any distros who ship the latter and not the former?
>

I can't talk about distro wide situation, but manual building gives only
one of the two. So there might be a situation where only one of the two
is present.

It seems we have a little dilemma here. Any suggestions how to solve it?


Thanks,
Justin


Attachments:
signature.asc (263.00 B)
OpenPGP digital signature

2013-03-01 08:37:01

by Sven Joachim

[permalink] [raw]
Subject: Re: [PATCH 2/2] kconfig: use config scripts to detect ncurses libs

On 2013-03-01 08:37 +0100, justin wrote:

> On 28/02/13 22:50, Sven Joachim wrote:
>> On 2013-02-28 10:59 +0100, [email protected] wrote:
>>
>>> Ncurses provides a config script (ncurses5-config) to assist finding ncurses.
>>> This patch makes use of it to detect the necessary libs for linking of the
>>> ncurses nconfig dialog.
>>
>> That script is not necessarily called ncurses5-config, it might also be
>> called ncurses6-config is ncurses is configured for a different ABI
>> (--enable-ext-colors, --enable-ext-mouse). Although I would suspect
>> that any distribution who does that provides a compatibility symlink.
>>
>
> We don't do that, but I rechecked with building ncurses manually. You
> are right. How widely spread is the usage of this options? Or is it
> rather an experimental option?

Pretty much, since it changes the ABI and everyone wants to be
compatible with the existing ncurses ABI.

> What we could do is simple extending the syntax to additionally check
> for the ABI version 6 config scripts. Is this an option to consider?

Probably.

>>> scripts/kconfig/Makefile | 4 +++-
>>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile
>>> index 3091794..c372976 100644
>>> --- a/scripts/kconfig/Makefile
>>> +++ b/scripts/kconfig/Makefile
>>> @@ -216,7 +216,9 @@ HOSTCFLAGS_gconf.o = `pkg-config --cflags gtk+-2.0 gmodule-2.0 libglade-2.0` \
>>>
>>> HOSTLOADLIBES_mconf = $(shell $(CONFIG_SHELL) $(check-lxdialog) -ldflags $(HOSTCC))
>>>
>>> -HOSTLOADLIBES_nconf = -lmenu -lpanel -lncurses
>>> +HOSTLOADLIBES_nconf = -lmenu -lpanel
>>> +HOSTLOADLIBES_nconf += $(shell ncursesw5-config --libs 2>/dev/null \
>>> + || ncurses5-config --libs 2>/dev/null )
>>
>> This will link with ncursesw, not ncurses. Probably not what you want,
>> since nconf.h does not #include the right headers for that.
>>
>
> That's true, and again it would change two things at once. I will go
> back to simple -lncurses as it was before.
>
>> On Debian/Ubuntu, there's also the problem that ncursesw5-config exists
>> even if the libncursesw5-dev package is not installed, so this patch
>> makes the build fail in such cases.
>
> Will be solved when reverting as described above. But actually it smells
> like a bug in the package management, doesn't it? Why are build time
> config scripts shipped in runtime only packages? What is their purpose?

Historically it seems to be an accident, and the ncurses{w,5}-config
scripts should have better been shipped in their development packages.
But nowadays we want to make the development packages multiarch-aware,
and since the scripts differ on architectures, moving them away from
ncurses-bin would mean adding two additional binary packages just for
these scripts.

See http://bugs.debian.org/480437 for a discussion on that topic.

>> Can we just call ncurses5-config and not ncursesw5-config, or are there
>> any distros who ship the latter and not the former?
>>
>
> I can't talk about distro wide situation, but manual building gives only
> one of the two. So there might be a situation where only one of the two
> is present.
>
> It seems we have a little dilemma here. Any suggestions how to solve it?

Well, at least until nconf does not make any effort to explicitly detect
and use the wide API, trying ncurses5-config first should work. If you
build ncurses yourself with --enable-widec, there is no -lmenu or -lpanel
anyway, these libraries are called menuw and panelw then.

Cheers,
Sven

2013-03-01 13:47:53

by justin

[permalink] [raw]
Subject: Re: [PATCH 2/2] kconfig: use config scripts to detect ncurses libs

On 01/03/13 09:36, Sven Joachim wrote:
> Historically it seems to be an accident, and the ncurses{w,5}-config
> scripts should have better been shipped in their development packages.
> But nowadays we want to make the development packages multiarch-aware,
> and since the scripts differ on architectures, moving them away from
> ncurses-bin would mean adding two additional binary packages just for
> these scripts.
>
> See http://bugs.debian.org/480437 for a discussion on that topic.
>

I just tested on an ubuntu installation what happens with the patches
applied; you simply end up with the warning the you need to install the
dev package. So I don't see any problem here.

> Well, at least until nconf does not make any effort to explicitly detect
> and use the wide API, trying ncurses5-config first should work. If you
> build ncurses yourself with --enable-widec, there is no -lmenu or -lpanel
> anyway, these libraries are called menuw and panelw then.

You are right, we only should consider ncurses5-config right now.

Regards,
Justin


Attachments:
signature.asc (263.00 B)
OpenPGP digital signature

2013-03-01 17:04:29

by Sven Joachim

[permalink] [raw]
Subject: Re: [PATCH 2/2] kconfig: use config scripts to detect ncurses libs

On 2013-03-01 14:47 +0100, justin wrote:

> On 01/03/13 09:36, Sven Joachim wrote:
>> Historically it seems to be an accident, and the ncurses{w,5}-config
>> scripts should have better been shipped in their development packages.
>> But nowadays we want to make the development packages multiarch-aware,
>> and since the scripts differ on architectures, moving them away from
>> ncurses-bin would mean adding two additional binary packages just for
>> these scripts.
>>
>> See http://bugs.debian.org/480437 for a discussion on that topic.
>>
>
> I just tested on an ubuntu installation what happens with the patches
> applied; you simply end up with the warning the you need to install the
> dev package. So I don't see any problem here.

Well, in Debian/Ubuntu are _two_ dev packages, one for the wide API
(libncursesw5-dev), and on for the non-wide API (libncurses5-dev). Only
the latter should be necessary, but with your original patch people
would need to install the former as well.

>> Well, at least until nconf does not make any effort to explicitly detect
>> and use the wide API, trying ncurses5-config first should work. If you
>> build ncurses yourself with --enable-widec, there is no -lmenu or -lpanel
>> anyway, these libraries are called menuw and panelw then.
>
> You are right, we only should consider ncurses5-config right now.

That seems unlikely to cause regressions on its own.

Cheers,
Sven