www.digitalmars.com         C & C++   DMDScript  

digitalmars.D - Creating a shared library under Linux?

reply Jens Mueller <jens.k.mueller gmx.de> writes:
Hi,

I've read several threads that about creating shared libraries. But I
could not make it work.
Does anybody know how to create a shared library? I don't care which
compiler I have to use to accomplish it.

Jens
Jul 26 2012
parent reply =?ISO-8859-1?Q?Alex_R=F8nne_Petersen?= <alex lycus.org> writes:
On 27-07-2012 07:23, Jens Mueller wrote:

 Hi,

 I've read several threads that about creating shared libraries. But I
 could not make it work.
 Does anybody know how to create a shared library? I don't care which
 compiler I have to use to accomplish it.

 Jens


Well, all three compilers (DMD, GDC, LDC) can create shared libraries at 
this point. But DMD doesn't actually ship libphobos2 (druntime+phobos) 
as a shared library yet, so this is not going to work out so well. If, 
however, you don't use stock libphobos2, you can pass -shared -fPIC to 
create a shared library.

GDC and LDC, as far as I know, can both create shared libraries. GDC 
does it with the standard options you'd pass to GCC. LDC's command line 
is very similar to DMD's if memory serves.

But (another one!): druntime is not yet ready to handle shared libraries 
properly. This means that exceptions thrown across library boundaries, 
TLS, etc are not likely to work properly.

So, in short: If you're using stock libphobos2, don't bother. If you're 
not using stock libphobos2, you can probably trivially create shared 
libraries.

-- 
Alex Rønne Petersen
alex lycus.org
http://lycus.org
Jul 26 2012
parent reply Jens Mueller <jens.k.mueller gmx.de> writes:
Alex R=F8nne Petersen wrote:

 On 27-07-2012 07:23, Jens Mueller wrote:

Hi,

I've read several threads that about creating shared libraries. But I
could not make it work.
Does anybody know how to create a shared library? I don't care which
compiler I have to use to accomplish it.

Jens


=20
 Well, all three compilers (DMD, GDC, LDC) can create shared
 libraries at this point. But DMD doesn't actually ship libphobos2
 (druntime+phobos) as a shared library yet, so this is not going to
 work out so well. If, however, you don't use stock libphobos2, you
 can pass -shared -fPIC to create a shared library.


But I can build druntime+phobos as shared libraries and then it should
work with dmd?


 GDC and LDC, as far as I know, can both create shared libraries. GDC
 does it with the standard options you'd pass to GCC. LDC's command
 line is very similar to DMD's if memory serves.


I tried both gdc and ldc but failed. I will write more specifically what
I did later.


 But (another one!): druntime is not yet ready to handle shared
 libraries properly. This means that exceptions thrown across library
 boundaries, TLS, etc are not likely to work properly.


I think I can avoid all of these limitations.


 So, in short: If you're using stock libphobos2, don't bother. If
 you're not using stock libphobos2, you can probably trivially create
 shared libraries.


I see. Then I will try to build a shared libphobos2 first.
Many thanks.

Jens
Jul 27 2012
parent reply =?ISO-8859-15?Q?Alex_R=F8nne_Petersen?= <alex lycus.org> writes:
On 27-07-2012 09:31, Jens Mueller wrote:

 Alex Rønne Petersen wrote:

 On 27-07-2012 07:23, Jens Mueller wrote:

 Hi,

 I've read several threads that about creating shared libraries. But I
 could not make it work.
 Does anybody know how to create a shared library? I don't care which
 compiler I have to use to accomplish it.

 Jens


 Well, all three compilers (DMD, GDC, LDC) can create shared
 libraries at this point. But DMD doesn't actually ship libphobos2
 (druntime+phobos) as a shared library yet, so this is not going to
 work out so well. If, however, you don't use stock libphobos2, you
 can pass -shared -fPIC to create a shared library.


 But I can build druntime+phobos as shared libraries and then it should
 work with dmd?


No, exceptions and TLS will still be broken, and the runtime doesn't 
know how to deal with shared libraries as they are loaded, so the GC 
might break in funny ways.


 GDC and LDC, as far as I know, can both create shared libraries. GDC
 does it with the standard options you'd pass to GCC. LDC's command
 line is very similar to DMD's if memory serves.


 I tried both gdc and ldc but failed. I will write more specifically what
 I did later.


 But (another one!): druntime is not yet ready to handle shared
 libraries properly. This means that exceptions thrown across library
 boundaries, TLS, etc are not likely to work properly.


 I think I can avoid all of these limitations.


Well, so long as you don't use exceptions and TLS, it might work. But I 
wouldn't recommend relying on it.


 So, in short: If you're using stock libphobos2, don't bother. If
 you're not using stock libphobos2, you can probably trivially create
 shared libraries.


 I see. Then I will try to build a shared libphobos2 first.
 Many thanks.

 Jens



-- 
Alex Rønne Petersen
alex lycus.org
http://lycus.org
Jul 27 2012
parent reply Mike Wey <mike-wey example.com> writes:
On 07/27/2012 09:33 AM, Alex Rønne Petersen wrote:

 On 27-07-2012 09:31, Jens Mueller wrote:

 Alex Rønne Petersen wrote:

 On 27-07-2012 07:23, Jens Mueller wrote:

 Hi,

 I've read several threads that about creating shared libraries. But I
 could not make it work.
 Does anybody know how to create a shared library? I don't care which
 compiler I have to use to accomplish it.

 Jens


 Well, all three compilers (DMD, GDC, LDC) can create shared
 libraries at this point. But DMD doesn't actually ship libphobos2
 (druntime+phobos) as a shared library yet, so this is not going to
 work out so well. If, however, you don't use stock libphobos2, you
 can pass -shared -fPIC to create a shared library.


 But I can build druntime+phobos as shared libraries and then it should
 work with dmd?


 No, exceptions and TLS will still be broken, and the runtime doesn't
 know how to deal with shared libraries as they are loaded, so the GC
 might break in funny ways.


 GDC and LDC, as far as I know, can both create shared libraries. GDC
 does it with the standard options you'd pass to GCC. LDC's command
 line is very similar to DMD's if memory serves.


 I tried both gdc and ldc but failed. I will write more specifically what
 I did later.


 But (another one!): druntime is not yet ready to handle shared
 libraries properly. This means that exceptions thrown across library
 boundaries, TLS, etc are not likely to work properly.


 I think I can avoid all of these limitations.


 Well, so long as you don't use exceptions and TLS, it might work. But I
 wouldn't recommend relying on it.


 So, in short: If you're using stock libphobos2, don't bother. If
 you're not using stock libphobos2, you can probably trivially create
 shared libraries.


 I see. Then I will try to build a shared libphobos2 first.
 Many thanks.

 Jens





I've successfully build GtkD as a shared library using LDC using the 
following steps:

Compiling the source files with fPIC:
ldc -O -m64 -relocation-model=pic -Isrc -c (source file)

Combine all the GtkD object file into one big object file:
ld -r (all GtkD object files) -o output.o

Create the shared lib using LDC:
ldc -shared output.so -L-soname=(so version) output.o

-- 
Mike Wey
Jul 27 2012
parent reply Jens Mueller <jens.k.mueller gmx.de> writes:
Mike Wey wrote:

 On 07/27/2012 09:33 AM, Alex R=F8nne Petersen wrote:

On 27-07-2012 09:31, Jens Mueller wrote:

Alex R=F8nne Petersen wrote:

On 27-07-2012 07:23, Jens Mueller wrote:

Hi,

I've read several threads that about creating shared libraries. But I
could not make it work.
Does anybody know how to create a shared library? I don't care which
compiler I have to use to accomplish it.

Jens


Well, all three compilers (DMD, GDC, LDC) can create shared
libraries at this point. But DMD doesn't actually ship libphobos2
(druntime+phobos) as a shared library yet, so this is not going to
work out so well. If, however, you don't use stock libphobos2, you
can pass -shared -fPIC to create a shared library.


But I can build druntime+phobos as shared libraries and then it should
work with dmd?


No, exceptions and TLS will still be broken, and the runtime doesn't
know how to deal with shared libraries as they are loaded, so the GC
might break in funny ways.


GDC and LDC, as far as I know, can both create shared libraries. GDC
does it with the standard options you'd pass to GCC. LDC's command
line is very similar to DMD's if memory serves.


I tried both gdc and ldc but failed. I will write more specifically what
I did later.


But (another one!): druntime is not yet ready to handle shared
libraries properly. This means that exceptions thrown across library
boundaries, TLS, etc are not likely to work properly.


I think I can avoid all of these limitations.


Well, so long as you don't use exceptions and TLS, it might work. But I
wouldn't recommend relying on it.


So, in short: If you're using stock libphobos2, don't bother. If
you're not using stock libphobos2, you can probably trivially create
shared libraries.


I see. Then I will try to build a shared libphobos2 first.
Many thanks.

Jens




=20
=20
 I've successfully build GtkD as a shared library using LDC using the
 following steps:
=20
 Compiling the source files with fPIC:
 ldc -O -m64 -relocation-model=3Dpic -Isrc -c (source file)
=20
 Combine all the GtkD object file into one big object file:
 ld -r (all GtkD object files) -o output.o
=20
 Create the shared lib using LDC:
 ldc -shared output.so -L-soname=3D(so version) output.o


Thanks a lot.
This does work if the last command is changed to
ldc2 -shared -of=3Doutput.so -L-soname=3D1 output.o
and ldc was built using -DBUILD_SHARED_LIBS=3DON.

Jens
Jul 29 2012
parent Mike Wey <mike-wey example.com> writes:
On 07/29/2012 02:34 PM, Jens Mueller wrote:

 Mike Wey wrote:

 I've successfully build GtkD as a shared library using LDC using the
 following steps:

 Compiling the source files with fPIC:
 ldc -O -m64 -relocation-model=pic -Isrc -c (source file)

 Combine all the GtkD object file into one big object file:
 ld -r (all GtkD object files) -o output.o

 Create the shared lib using LDC:
 ldc -shared output.so -L-soname=(so version) output.o


 Thanks a lot.
 This does work if the last command is changed to
 ldc2 -shared -of=output.so -L-soname=1 output.o
 and ldc was built using -DBUILD_SHARED_LIBS=ON.

 Jens



I looks like i didn't get the soname quite right, it should have been:
ldc -shared output.so -L-soname=output.so.(so version) output.o


the soname is the name of the library ld will try to load at program 
startup. if you are not going to use to typical linux approach of 
setting up symlinks to get both a versioned and a unversioned lib in the 
filesystem. Then you don't have to specify a somane as the default 
soname is the name of the lib.

-- 
Mike Wey
Jul 29 2012