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On 8 May 2007, at 22:01, Fabian Groffen wrote: |
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> The compiler, linker and runtime linker all default to /usr/local/lib, |
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> /usr/lib, /lib to search for libraries. This means, (also on |
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> Darwin in |
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> a way) that if there is no path given for a dynamic library, it is |
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> searched for in those three paths. You can influence that by |
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> setting a |
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> special variable, but that's in general considered to be a bad |
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> practise. |
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I think there will always be a path for a dynamic library: if one |
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wasn't set using -install_name, then whatever was given to -o will be |
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used. Every dynamic library has itself as a dependency, and this |
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dependency will end up as a dependency of whatever links against the |
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library. |
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> In Gentoo the libraries are never copied, but on GNU/ELF systems, |
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> LD-wrapper scripts are made. Because Darwin (and more systems) don't |
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> grok those scripts, we create symlinks for those systems. The reason |
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> why this is done, is because in some cases GCC decides to make a |
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> static |
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> binary instead of a dynamic one if it doesn't see a dynamic library in |
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> /usr/lib. I don't know the details of this, it's what I know from the |
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> eclass that does this creating of the wrapper or symlink. |
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I didn't know this. |
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>>> ncurses patch: no way, the main tree does it like that, so not |
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>>> going to |
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>>> change that. |
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>> |
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>> ncurses is configured with --libdir=/lib. Then, whatever parts |
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>> aren't |
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>> needed in /lib are moved to /usr/lib, with the effect that moved |
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>> items |
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>> would no longer be found in /lib. What I tried to do was to |
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>> configure with |
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>> --libdir=/usr/lib, move necessary things to /lib and create links |
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>> where the |
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>> moved things used to be. |
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Maybe I misunderstood something, but to me the idea is to _avoid_ |
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moving stuff from their install location _without_ leaving a symlink/ |
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wrapper behind. If stuff is moved without leaving something behind, |
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the linker will have to search for it elsewhere. |
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In the case of ncurses, libraries configured to /lib are moved to / |
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usr/lib without leaving symlinks/wrappers in /lib. Because most libs |
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will actually end up in /usr/lib, I thought configuring to /usr/lib |
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and then moving stuff to /lib while leaving suitable symlinks/ |
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wrappers in /usr/lib would be sensible. |
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>>> readline patch: I don't understand it |
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>> |
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>> readline is configured with --libdir=/usr/lib. Then all libraries |
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>> are |
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>> moved to /lib. I wanted to create symlinks for all libraries |
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>> moved. I |
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>> guess the intention would have been clearer if I had configured with |
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>> --libdir=/lib and skipped the move altogether (not tested). |
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What I don't understand is why readline is configured to /usr/lib if |
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everything is going to be moved to /lib anyway? To me it seems |
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clearer to configure to /lib, and then create whatever symlinks/ |
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wrappers in /usr/lib are needed to prevent static linking. |
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> It's good to put it on the table. I was a bit in a hurry when I |
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> replied, so I forgot to say that I like the feedback. I think |
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> there is |
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> no better way than keeping all platforms aligned wherever this is |
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> possible. And this library location problem seems to be not a problem |
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> on Darwin, but it does affect existing users, unfortunately. However, |
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> it is a one-time pain, and a risk of running the highly experimental |
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> Gentoo Alt/Prefix project ;) |
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I'm all for alignment, too. And I have a lot to learn! |
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// Cheers; Johan |
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-- |
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