Folks I have a bug report against Boost.Config that I don't know what (if anything) I should do about: https://github.com/boostorg/config/issues/243 The issue is this: lets say I build boost as static libraries with -fvisibilty=hidden because I want my application or shared library to *hide all boost symbols*. But there are some parts of boost which unconditionally make things visible - throw_exception is one particular culprit, but there are others, probably anything which uses BOOST_SYMBOL_VISIBLE in fact. Question: should we support this? If so how? The only thing I can think of is a user-defined macro which when set, disables symbol visibility. Thoughts? Thanks, John. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
On 9/25/18 8:08 PM, John Maddock via Boost wrote:
Folks I have a bug report against Boost.Config that I don't know what (if anything) I should do about: https://github.com/boostorg/config/issues/243
The issue is this: lets say I build boost as static libraries with -fvisibilty=hidden because I want my application or shared library to *hide all boost symbols*. But there are some parts of boost which unconditionally make things visible - throw_exception is one particular culprit, but there are others, probably anything which uses BOOST_SYMBOL_VISIBLE in fact.
Question: should we support this? If so how? The only thing I can think of is a user-defined macro which when set, disables symbol visibility.
I don't think we need to support this sice the user can already hide any symbols with linker scripts. http://man7.org/conf/lca2006/shared_libraries/slide18c.html Also, a thing to note is that I think there are a few places where Boost relies on some symbols being defined by user, which means they should be either defined in the same executable or exported from another. For instance, tss_cleanup_implemented from Boost.Thread works like this.
On Tue, Sep 25, 2018 at 10:29 AM Andrey Semashev via Boost < boost@lists.boost.org> wrote:
On 9/25/18 8:08 PM, John Maddock via Boost wrote:
Folks I have a bug report against Boost.Config that I don't know what (if anything) I should do about: https://github.com/boostorg/config/issues/243
The issue is this: lets say I build boost as static libraries with -fvisibilty=hidden because I want my application or shared library to *hide all boost symbols*. But there are some parts of boost which unconditionally make things visible - throw_exception is one particular culprit, but there are others, probably anything which uses BOOST_SYMBOL_VISIBLE in fact.
Question: should we support this? If so how? The only thing I can think of is a user-defined macro which when set, disables symbol visibility.
I don't think we need to support this sice the user can already hide any symbols with linker scripts.
I've seen this done, and it was extraordinarily painful. To me the need for this is a vote in favor of supporting this feature request, no against. Having said that, the only reason I know of that any of this should actually be required is in an environment where only static linking is allowed (e.g. a game console). Is there a reason the requester could not just link to Boost dynamically? Zach
On 25.09.18 19:38, Zach Laine via Boost wrote:
On Tue, Sep 25, 2018 at 10:29 AM Andrey Semashev via Boost < boost@lists.boost.org> wrote:
On 9/25/18 8:08 PM, John Maddock via Boost wrote:
Folks I have a bug report against Boost.Config that I don't know what (if anything) I should do about: https://github.com/boostorg/config/issues/243
The issue is this: lets say I build boost as static libraries with -fvisibilty=hidden because I want my application or shared library to *hide all boost symbols*. But there are some parts of boost which unconditionally make things visible - throw_exception is one particular culprit, but there are others, probably anything which uses BOOST_SYMBOL_VISIBLE in fact.
Question: should we support this? If so how? The only thing I can think of is a user-defined macro which when set, disables symbol visibility.
I don't think we need to support this sice the user can already hide any symbols with linker scripts.
I've seen this done, and it was extraordinarily painful. To me the need for this is a vote in favor of supporting this feature request, no against. Having said that, the only reason I know of that any of this should actually be required is in an environment where only static linking is allowed (e.g. a game console).
Is there a reason the requester could not just link to Boost dynamically?
If you have a plugin that links to boost, and this plugin should be loaded by another program that links to another version of boost, you may have symbol clashes (mostly on Linux). Dynamic linking does not help: a symbol may be overridden by a remote library. Raffi
On Tue, Sep 25, 2018 at 12:55 PM Raffi Enficiaud via Boost < boost@lists.boost.org> wrote:
On Tue, Sep 25, 2018 at 10:29 AM Andrey Semashev via Boost < boost@lists.boost.org> wrote:
On 9/25/18 8:08 PM, John Maddock via Boost wrote:
Folks I have a bug report against Boost.Config that I don't know what (if anything) I should do about: https://github.com/boostorg/config/issues/243
The issue is this: lets say I build boost as static libraries with -fvisibilty=hidden because I want my application or shared library to *hide all boost symbols*. But there are some parts of boost which unconditionally make things visible - throw_exception is one particular culprit, but there are others, probably anything which uses BOOST_SYMBOL_VISIBLE in fact.
Question: should we support this? If so how? The only thing I can think of is a user-defined macro which when set, disables symbol visibility.
I don't think we need to support this sice the user can already hide any symbols with linker scripts.
I've seen this done, and it was extraordinarily painful. To me the need for this is a vote in favor of supporting this feature request, no against. Having said that, the only reason I know of that any of this should actually be required is in an environment where only static
On 25.09.18 19:38, Zach Laine via Boost wrote: linking
is allowed (e.g. a game console).
Is there a reason the requester could not just link to Boost dynamically?
If you have a plugin that links to boost, and this plugin should be loaded by another program that links to another version of boost, you may have symbol clashes (mostly on Linux). Dynamic linking does not help: a symbol may be overridden by a remote library.
Thanks, Rafi. I find that to be compelling use case. Is the proposed fix going to increase library authors' maintenance burdens? Zach
On 25.09.18 20:08, Zach Laine via Boost wrote:
On Tue, Sep 25, 2018 at 12:55 PM Raffi Enficiaud via Boost < boost@lists.boost.org> wrote:
On Tue, Sep 25, 2018 at 10:29 AM Andrey Semashev via Boost < boost@lists.boost.org> wrote:
On 9/25/18 8:08 PM, John Maddock via Boost wrote:
Folks I have a bug report against Boost.Config that I don't know what (if anything) I should do about: https://github.com/boostorg/config/issues/243
The issue is this: lets say I build boost as static libraries with -fvisibilty=hidden because I want my application or shared library to *hide all boost symbols*. But there are some parts of boost which unconditionally make things visible - throw_exception is one particular culprit, but there are others, probably anything which uses BOOST_SYMBOL_VISIBLE in fact.
Question: should we support this? If so how? The only thing I can think of is a user-defined macro which when set, disables symbol visibility.
I don't think we need to support this sice the user can already hide any symbols with linker scripts.
I've seen this done, and it was extraordinarily painful. To me the need for this is a vote in favor of supporting this feature request, no against. Having said that, the only reason I know of that any of this should actually be required is in an environment where only static
On 25.09.18 19:38, Zach Laine via Boost wrote: linking
is allowed (e.g. a game console).
Is there a reason the requester could not just link to Boost dynamically?
If you have a plugin that links to boost, and this plugin should be loaded by another program that links to another version of boost, you may have symbol clashes (mostly on Linux). Dynamic linking does not help: a symbol may be overridden by a remote library.
Thanks, Rafi. I find that to be compelling use case. Is the proposed fix going to increase library authors' maintenance burdens?
My opinion is that this is not a job for a C++ developer and/or library maintainer. Also, we are not shipping compilers with STL or what not, and we never claimed to ensure ABI compatibility across versions. All those tasks are related, and this is "packaging" to me. This is hard work, and I believe we have already enough to do :) Of course, this is my opinion :) Raffi
On 9/25/2018 1:08 PM, John Maddock via Boost wrote:
Folks I have a bug report against Boost.Config that I don't know what (if anything) I should do about: https://github.com/boostorg/config/issues/243
The issue is this: lets say I build boost as static libraries with -fvisibilty=hidden because I want my application or shared library to *hide all boost symbols*. But there are some parts of boost which unconditionally make things visible - throw_exception is one particular culprit, but there are others, probably anything which uses BOOST_SYMBOL_VISIBLE in fact.
Question: should we support this? If so how? The only thing I can think of is a user-defined macro which when set, disables symbol visibility.
Thoughts?
Isn't it up to each built library to determine what symbols should be visible or not in order to use that library ? In general public and protected class functionality should be visible, and functions which are part of the library's public interface are visible, with everything else remaining hidden. If an end-user wants to override this for some personal reason there should be a mechanism for doing so, but I would normally see little reason why an end-user should want to do that. What harm can it be to allow normally visible symbols to remain visible for the end-user ?
Thanks, John.
On 25.09.18 19:08, John Maddock via Boost wrote:
Folks I have a bug report against Boost.Config that I don't know what (if anything) I should do about: https://github.com/boostorg/config/issues/243
The issue is this: lets say I build boost as static libraries with -fvisibilty=hidden because I want my application or shared library to *hide all boost symbols*. But there are some parts of boost which unconditionally make things visible - throw_exception is one particular culprit, but there are others, probably anything which uses BOOST_SYMBOL_VISIBLE in fact.
Question: should we support this? If so how? The only thing I can think of is a user-defined macro which when set, disables symbol visibility.
Thoughts?
Thanks, John.
I was trying to do that for a Matlab extension that had dependencies on Boost. The symbols of my extension were clashing with the Boost shipped with Matlab. My findings were that the hidden (+/- inline) visibility helps a bit, but does not make boost totally invisible. You will need additional compiler options on Linux and OSX. One of those compiler options is the map file that indicates which symbols should be exported, in a verbose fashion. Example of map file: https://github.com/MPI-IS/Grassmann-Averages-PCA/blob/master/extensions/Matl... How to inject this in the build: https://github.com/MPI-IS/Grassmann-Averages-PCA/blob/master/CMakeLists.txt#... Concerning the exceptions, if their handling is internal to the library, I believe they can stay hidden. If they need to be caught, they obviously need to be exported. My opinion is that that those things are rather "integration" or "system" level that depend on different scenarios and environments. I do not think that this work should be shifted from library or package integrators to boost C++ developers. Best regards, Raffi
John Maddock wrote:
Folks I have a bug report against Boost.Config that I don't know what (if anything) I should do about: https://github.com/boostorg/config/issues/243
The issue is this: lets say I build boost as static libraries with -fvisibilty=hidden because I want my application or shared library to *hide all boost symbols*. But there are some parts of boost which unconditionally make things visible - throw_exception is one particular culprit, but there are others, probably anything which uses BOOST_SYMBOL_VISIBLE in fact.
Question: should we support this? If so how? The only thing I can think of is a user-defined macro which when set, disables symbol visibility.
That's the only thing we can do. #ifdef something, #define BOOST_SYMBOL_VISIBLE to nothing, let them deal with whatever happens.
вт, 25 сент. 2018 г. в 21:08, Peter Dimov via Boost
John Maddock wrote: <...>
Question: should we support this? If so how? The only thing I can think of is a user-defined macro which when set, disables symbol visibility.
That's the only thing we can do. #ifdef something, #define BOOST_SYMBOL_VISIBLE to nothing, let them deal with whatever happens.
+1. Do that and let people seek and hide symbols. -- Best regards, Antony Polukhin
participants (7)
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Andrey Semashev -
Antony Polukhin -
Edward Diener -
John Maddock -
Peter Dimov -
Raffi Enficiaud -
Zach Laine