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digitalmars.D - Shared libraries under linux

reply alexhairyman <alexhairyman gmail.com> writes:
Just a tip for everybody, but Under Linux, you can do a lot with the Linker
commands you know those -L ones, besides being able to link with shared, you
can also specify where the ELF binary will look to find your D shared library,
by using -L-r which embeds a search path in your ELF binary, handy for
updateable libraries, or a plugin system. I have a complete example somewhere
on my laptop if anyone is interested. This is a native feature of ld so it
should work almost anywhere.

-- 
alexhairyman <alexhairyman gmail.com>
Apr 16 2012
next sibling parent reply "Sven-Hendrik Haase" <sh lutzhaase.com> writes:
On Tuesday, 17 April 2012 at 00:41:46 UTC, alexhairyman wrote:

 Just a tip for everybody, but Under Linux, you can do a lot 
 with the Linker commands you know those -L ones, besides being 
 able to link with shared, you can also specify where the ELF 
 binary will look to find your D shared library, by using -L-r 
 which embeds a search path in your ELF binary, handy for 
 updateable libraries, or a plugin system. I have a complete 
 example somewhere on my laptop if anyone is interested. This is 
 a native feature of ld so it should work almost anywhere.


For a plugin system, wouldn't you use dlopen and link to dl?

Also, you might as well use LD_LIBRARY_PATH and rpath-stripped 
libs/bins instead which seems like the cleaner solution to me.
Apr 16 2012
parent reply alexhairyman <alexhairyman gmail.com> writes:
On Tue, 17 Apr 2012 02:46:28 +0200
"Sven-Hendrik Haase" <sh lutzhaase.com> wrote:


 On Tuesday, 17 April 2012 at 00:41:46 UTC, alexhairyman wrote:

 Just a tip for everybody, but Under Linux, you can do a lot 
 with the Linker commands you know those -L ones, besides being 
 able to link with shared, you can also specify where the ELF 
 binary will look to find your D shared library, by using -L-r 
 which embeds a search path in your ELF binary, handy for 
 updateable libraries, or a plugin system. I have a complete 
 example somewhere on my laptop if anyone is interested. This is 
 a native feature of ld so it should work almost anywhere.


 
 For a plugin system, wouldn't you use dlopen and link to dl?
 
 Also, you might as well use LD_LIBRARY_PATH and rpath-stripped 
 libs/bins instead which seems like the cleaner solution to me.


True, that was an excited blurb of misinformation I gave there, but rpath keeps
you from having to use LD_LIBRARY_PATH which would require you to add a script
to first set, then call the application, and while it is not much of a burden,
it makes things a little bit easier to use. And is there a way to use libdl in
a "D-ish" way? I remember the Old c++ way being a bit sloppy but not at all
bad, simply requiring you to create a function that returned a class (if my
memory decides to work).And the DDl project is dead for now, and shows little
hope of revival. If someone could point me in the direction of a similar
library I would very much appreciate it! And yes, the plugin system would be
nearly impossible (if not outright)

-- 
alexhairyman <alexhairyman gmail.com>
Apr 16 2012
parent reply Jens Mueller <jens.k.mueller gmx.de> writes:
alexhairyman wrote:

 On Tue, 17 Apr 2012 02:46:28 +0200
 "Sven-Hendrik Haase" <sh lutzhaase.com> wrote:
 

 On Tuesday, 17 April 2012 at 00:41:46 UTC, alexhairyman wrote:

 Just a tip for everybody, but Under Linux, you can do a lot 
 with the Linker commands you know those -L ones, besides being 
 able to link with shared, you can also specify where the ELF 
 binary will look to find your D shared library, by using -L-r 
 which embeds a search path in your ELF binary, handy for 
 updateable libraries, or a plugin system. I have a complete 
 example somewhere on my laptop if anyone is interested. This is 
 a native feature of ld so it should work almost anywhere.


 
 For a plugin system, wouldn't you use dlopen and link to dl?
 
 Also, you might as well use LD_LIBRARY_PATH and rpath-stripped 
 libs/bins instead which seems like the cleaner solution to me.


 
 True, that was an excited blurb of misinformation I gave there, but
 rpath keeps you from having to use LD_LIBRARY_PATH which would require
 you to add a script to first set, then call the application, and while
 it is not much of a burden, it makes things a little bit easier to
 use. And is there a way to use libdl in a "D-ish" way? I remember the
 Old c++ way being a bit sloppy but not at all bad, simply requiring
 you to create a function that returned a class (if my memory decides
 to work).And the DDl project is dead for now, and shows little hope of
 revival. If someone could point me in the direction of a similar
 library I would very much appreciate it! And yes, the plugin system
 would be nearly impossible (if not outright)


Does this http://jkm.github.com/ddl/ddl.html work for you? I welcome any
kind of feedback.

Jens
Apr 17 2012
parent "alexhairyman" <alexhairyman gmail.com> writes:
On Tuesday, 17 April 2012 at 07:28:14 UTC, Jens Mueller wrote:

 alexhairyman wrote:

 On Tue, 17 Apr 2012 02:46:28 +0200
 "Sven-Hendrik Haase" <sh lutzhaase.com> wrote:
 

 On Tuesday, 17 April 2012 at 00:41:46 UTC, alexhairyman 
 wrote:

 Just a tip for everybody, but Under Linux, you can do a 
 lot with the Linker commands you know those -L ones, 
 besides being able to link with shared, you can also 
 specify where the ELF binary will look to find your D 
 shared library, by using -L-r which embeds a search path 
 in your ELF binary, handy for updateable libraries, or a 
 plugin system. I have a complete example somewhere on my 
 laptop if anyone is interested. This is a native feature 
 of ld so it should work almost anywhere.


 
 For a plugin system, wouldn't you use dlopen and link to dl?
 
 Also, you might as well use LD_LIBRARY_PATH and 
 rpath-stripped libs/bins instead which seems like the 
 cleaner solution to me.


 
 True, that was an excited blurb of misinformation I gave 
 there, but
 rpath keeps you from having to use LD_LIBRARY_PATH which would 
 require
 you to add a script to first set, then call the application, 
 and while
 it is not much of a burden, it makes things a little bit 
 easier to
 use. And is there a way to use libdl in a "D-ish" way? I 
 remember the
 Old c++ way being a bit sloppy but not at all bad, simply 
 requiring
 you to create a function that returned a class (if my memory 
 decides
 to work).And the DDl project is dead for now, and shows little 
 hope of
 revival. If someone could point me in the direction of a 
 similar
 library I would very much appreciate it! And yes, the plugin 
 system
 would be nearly impossible (if not outright)


 Does this http://jkm.github.com/ddl/ddl.html work for you? I 
 welcome any
 kind of feedback.

 Jens


O_o YES! Will definitely check this out!
Apr 17 2012
prev sibling parent "Martin Nowak" <dawg dawgfoto.de> writes:
On Tue, 17 Apr 2012 02:41:45 +0200, alexhairyman <alexhairyman gmail.com>  
wrote:


 Just a tip for everybody, but Under Linux, you can do a lot with the  
 Linker commands you know those -L ones, besides being able to link with  
 shared, you can also specify where the ELF binary will look to find your  
 D shared library, by using -L-r which embeds a search path in your ELF  
 binary, handy for updateable libraries, or a plugin system. I have a  
 complete example somewhere on my laptop if anyone is interested. This is  
 a native feature of ld so it should work almost anywhere.


http://fedoraproject.org/wiki/Packaging:Guidelines#Beware_of_Rpath
Apr 17 2012