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On Sunday 06 January 2008, Matthijs Kooijman wrote: |
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> I've been trying to get alsa to work with uclibc and found out that it |
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> breaks against uclibc when using versioned symbols. |
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i hit this elsewhere, but forgot to push my experience back in Gentoo. sorry |
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about that. |
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> As far as I understand, uclibc doesn't support versioned symbols. However, |
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> the default gentoo-embedded toolchain is happy to compile binaries with |
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> versioned symbols. So, there are no problems at compile or link time. |
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correct. we'll add optional version support to uClibc at some point, but |
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that'll be some time away and most likely turned off by default as ABI |
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compatibility is a back seat in embedded world. |
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> However, at runtime, the dynamic module loader (I think?) ignores the |
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> versions on symbols and just picks some symbol to link against. In my case, |
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> pulseaudio linked against the symbols from the old alsa api (so not even |
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> the default version). This resulted in some hard to debug breakage. |
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uClibc's ldso skips over any dynamic tags related to symbol versioning. i |
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looked at adding warnings/errors like is done with TEXTRELs, but it seems |
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that it is not possible to disable these things completely in the core libs |
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that come from gcc. btw, we should consider adding --disable-symvers in |
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toolchain.eclass for uClibc/gcc ... |
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when looking for symbols, uClibc simply walks until it finds the first match. |
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> The solution to this problem turned out to be compiling alsa-lib with |
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> --without-versioned. This way, only the default version of each symbol is |
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> compiled, and no version information is added. |
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yep |
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> 1. Add an alsa-compat use flag to alsa-libs. Only compile also with |
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> 2. Add a symver (global?) useflag. This usefalg does the same as the |
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> 3. Modify the configure script of alsa-lib (probably upstream). The current |
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(1) is no good. (2) will probably be realistic down the line, but not until |
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uClibc actually supports it. (3) is certainly not the route we want to go. |
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i'll commit like Ned said and tie it to elibc_uclibc to --without-versioned |
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-mike |
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