[Scons-dev] Versioned libraries: non-standard sonames

[David García Garzón]

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El 01/01/14 00:30, William Deegan ha escrit:

> David,

>

>

> On Dec 31, 2013, at 10:12 AM, David García Garzón

<david.garcia at upf.edu> wrote:

>

>> I've been trying out the versioned libraries feature. As I said i do

>> like the nice interface you guys finally got. But i would like to

>> comment two issues i found. I open this thread about the first one:

>> Non-standard Sonames

>>

>> Current implementation forces you to set the major version number as the

>> soname suffix for your library. This is convenient in many cases, but

>> this doesn't cover the undesiderable but real cases in which the soname

>> must be changed more than once between major versions.

>

>

>>

>> Indeed in our project we left the first version for API changes, and the

>> second version for ABI changes and the last one for ABI safe changes. So

>> our soname has two version numbers and i think we are not a rare case.

>> Indeed some projects have unrelated sonames and library names, that is

>> far from ideal but real. So in general, i see convenient to be able to

>> explicitly set the soversion for the library.

>>

>> The solution i am thinkin on, in pseudo-python, would be:

>>

>> soname = (

>>  $SONAME if $SONAME else

>>  libname+$SOVERSION if $SOVERSION else

>>  libname+majorversion($SHLIBVERSION) if $SHLIBVERSION

>> )

>>

>> So, how do you feel about this feature? I feel bold to implement it

>> myself, so give me a bless and i'll go for it.

>

> So what would a linker command line look like for your use model?

> -Bill


Structurally the command line does not change. At some point we add the
"-Wl,-soname=%s" flag in gcc tool chain specifying the soname and then
we create the symlink with the same name specified at the flag. I am
just arguing about how to compute such soname.

My suggestion would be adding the following flag instead:

    -Wl,-soname="$SONAME"

And then defining SONAME by default as something like:

    env["SONAME"]="$SHLIBPREFIX$TARGET$SHLIBSUFFIX.$ABIVERSION"
   
env["ABIVERSION"]="${'.'.join(SHLIBVERSION.split('.')[:ABIVERSIONLEVELS])}"
    env["ABIVERSIONLEVELS"]=1

I just renamed previous SOVERSION as ABIVERSION because SONAME is
posix/linux centric and ABI compatibility version is a crossplatform
concept. I am opening a different discussion thread on this because i
think we are using it badly in Darwin and not using it at all in windows
platforms (cygwin, msvc and mingw).

David.

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