[FFmpeg-user] --extra-ldflags not working

Reindl Harald h.reindl at thelounge.net
Sun Mar 27 21:03:20 CEST 2016

Am 27.03.2016 um 20:58 schrieb Aaron Boxer:
> On Sun, Mar 27, 2016 at 2:46 PM, Reindl Harald <h.reindl at thelounge.net>
> wrote:
>> Am 27.03.2016 um 15:53 schrieb Aaron Boxer:
>>> On Sun, Mar 27, 2016 at 9:33 AM, Reindl Harald <h.reindl at thelounge.net>
>>> wrote:
>>>> Am 27.03.2016 um 15:23 schrieb Aaron Boxer:
>>>> Dear List,
>>>>> I am still troubleshooting linking to a local build of openjpeg.
>>>>> This is a static build of openjpeg, and the library  libopenjp2.a
>>>>> is placed in the /usr/local/lib folder.
>>>>> (I am on Ubuntu)
>>>>> My configure command is:
>>>>> . $ ./configure --enable-libopenjpeg
>>>>> --extra_cflags="-DHAVE_OPEN_OPENJPEG_2_1_OPENJPEG_H"
>>>>> --extra-ldflags="-L/usr/local/lib"
>>>>> But this fails with a "libopenjpeg not found" error
>>>> .a files are for static linking
>>>> .so files are for dynamic linking
>>> --enable-static --extra-cflags='-I/usr/local/x264'
>>>> --extra-ldflags='-I/usr/local/x264 -L/usr/local/x264 -ldl'
>>>> Thanks, but linking is not the problem. The problem is locating the .a
>>> file.
>>> I did try --enable static, but doesn't help
>> what about read the other parts of my reply?
> Ahhh, sorry, missed that one.   That will really help me, because i would
> rather link to the shared
> version, rather than the static.

why don't you then just delete the .la files?
on Fedora at example they are prohibited and deleted by any builds

> So, I tried adding  -ldl,

-ldl is only *one piece* of what i showed you and was suggested years 
ago to solve the goal build a static ffmpeg with a static libx264

> but when I look in config.log, I see
> /usr/local/lib/libopenjp2.so Undefined reference to `dlopen`
> /usr/local/lib/libopenjp2.so Undefined reference to `dlclose`
> Now, my library uses the dlopen and dlclose system calls to load another
> shared library.
> So, it looks like I need to tell configure to link to the system library
> that has the dlopen and dlclose symbols

no idea, the sample above is how to link a static x264 by intention to 
have the option use a newer one without collide with the system packages 
used by other packages

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