[Jason Merrill <[e-mail]>] Re: [jamboost] <link> --- tweaks

From: David Abrahams (dave_at_[hidden])
Date: 2002-12-09 11:17:26

Just in case Jason isn't allowed to post...

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To: David Abrahams <dave_at_[hidden]>
Cc: jamboost_at_[hidden]
Subject: Re: [jamboost] <link> --- tweaks
References: <3DF4687D.5070803_at_[hidden]> <ubs3vi53h.fsf_at_[hidden]>
From: Jason Merrill <jason_at_[hidden]>
In-Reply-To: <ubs3vi53h.fsf_at_[hidden]> (David Abrahams's message
of "Mon, 09 Dec 2002 10:28:50 -0500")
Date: Mon, 09 Dec 2002 10:45:28 -0500
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On Mon, 09 Dec 2002 10:28:50 -0500, David Abrahams <dave_at_[hidden]> wrote:

> Vladimir Prus <ghost_at_[hidden]> writes:
>
>> Okay, I've nearly done with the <link> feauture and
>> associated support for -l libraries. I do have a couple
>> of questions for gcc gurus.
>>
>> 1. If I have two libraries, "a", and "b", and want to link
>> the first one statically, and the second one dynamically,
>> what should command line contain.
>> If I try
>>
>> -Wl,-Bdynamic -la -Wl,-Bstatic -lb
>>
>> then it works on certain system. On another, this links
>> both libraries statically, and I need
>>
>> -Wl,-Bdynamic -Wl,-la -Wl,-Bstatic -Wl,-lb
>
> Hmm, this looks like some strangeness in the g++ front-end to the
> linker. Jason, do you know anything about this?

The g++ driver moves any explicit -lm and -lc to the end of the command
line so that they come after the implicit -lstdc++. Other libs should be
unaffected.

>> 2. Is it ever possible to link to static runtime if any lib
>> is dynamic? For example, in default setting both "-lm" and "-lc"
>> are linked dynamically. If I say
>>
>> -Wl,-Bdynamic -lz -Wl,Bstatic
>>
>> (here, the last element should affect runtime libs).
>>
>> Then, -lz is linked dynamically (that's right),
>> "-lm" is linked statically (that's right, too), 
>
> How did libm get involved? I don't see it in the command-line.

libstdc++ often depends on libm, so it's added implicitly.

Jason
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-- 
David Abrahams
dave_at_[hidden] * http://www.boost-consulting.com
Boost support, enhancements, training, and commercial distribution
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