[Libav-user] Beginner c++ compiling error

jan hölscher jan.hoelscher at codergrid.de
Sat Oct 1 22:40:03 CEST 2011


Okt, could you give us  an example of which function name could not be
resolved?
Am 01.10.2011 22:28 schrieb "mounir younes" <mounir.younes at gmail.com>:
> i am using netbeans and in the libraries tab there is a linker command
where
> i am adding the libs i stated in the thread before. Netbeans is catching
the
> libs (giving them a lib icon otherwise it would've given them a "blank"
> icon) but I am always getting the "undefined reference to <functionName>"
> (when using ffmpeg functions). I would really appreciate it if someone can
> write a really really really small tutorial that shows how to build ur
first
> ffmpeg program (using the latest ffmpeg) and run it. That would help a lot
> of people other than me for a lot of people are having this problem and
some
> others after updating ffmpeg.
>
> On Thu, Sep 29, 2011 at 1:39 AM, jan hölscher <jan.hoelscher at codergrid.de
>wrote:
>
>> before we can discuss further, please provide the complete command line
to
>> the linker and error from it.
>>
>>
>>
>> 2011/9/29 mounir younes <mounir.younes at gmail.com>
>>
>>> Yes I did that ! But still having the problem after building.
>>>
>>>
>>> On Wed, Sep 28, 2011 at 7:53 PM, jan hölscher <
jan.hoelscher at codergrid.de
>>> > wrote:
>>>
>>>> did you surround your libav header includes with :
>>>>
>>>> #ifdef __cplusplus
>>>> extern "C" {
>>>> #endif
>>>> #include <libavformat/avformat.h>
>>>> #include <libavcodec/avcodec.h>
>>>> #include <libavcodec/opt.h>
>>>> #include <libavutil/avutil.h>
>>>> #include <libswscale/swscale.h>
>>>> #include <libavutil/fifo.h>
>>>> #include <libavutil/rational.h>
>>>> #ifdef __cplusplus
>>>> }
>>>> #endif
>>>>
>>>>
>>>> 2011/9/28 mounir younes <mounir.younes at gmail.com>
>>>>
>>>>> I gave the names without the linker prefix. I keep getting the
>>>>> "undefined reference to" error and cannot solve it.
>>>>>
>>>>> On Sat, Sep 24, 2011 at 10:43 PM, Alex Cohn <alexcohn at netvision.net.il
>wrote:
>>>>>
>>>>>> In your list of libs, "-l" is obviously doubled. Try to give the
names
>>>>>> to the linker without the prefix.
>>>>>> On Sep 24, 2011 7:58 AM, "mounir younes" <mounir.younes at gmail.com>
>>>>>> wrote:
>>>>>> > Hello, I am new to ffmpeg and I am getting compiling errors while
>>>>>> compiling
>>>>>> > c++ code with ffmpeg libraries. It seems that a lot of people are
>>>>>> getting
>>>>>> > this with the new ffmpeg but I couldn't find a solution that I
could
>>>>>> > understand.
>>>>>> >
>>>>>> > I found a link that says that this
>>>>>> >
>>>>>> > CXXFLAGS=-D__STDC_CONSTANT_MACROS ./configure
>>>>>> > (http://code.google.com/p/ffmpegsource/issues/detail?id=11)
>>>>>> >
>>>>>> >
>>>>>> > solves it but unfortunately I tried it but nothing happened and I
>>>>>> don't know
>>>>>> > what to do ! I am adding the file headers which are being
>>>>>> automatically
>>>>>> > detected by netbeans so the libraries are already found. I tried
>>>>>> adding
>>>>>> > these -lavdevice -lavformat -lavcodec -lavutil -lswscale -lbz2 to
the
>>>>>> > linker as well
>>>>>> >
>>>>>> > (
>>>>>> >
>>>>>>
http://libav-users.943685.n4.nabble.com/QT-and-FFmpeg-undefined-reference-to-av-free-and-more-td946811.html
>>>>>> > )
>>>>>> >
>>>>>> > when adding them netbeans knew them and gave them proper library
>>>>>> icons (thus
>>>>>> > it recognized that these libraries are present otherwise it
would've
>>>>>> > replaced them with a white icon with question mark). But, when
>>>>>> compiling I
>>>>>> > get this
>>>>>> >
>>>>>> > /usr/bin/ld: cannot find -l-lavdevice
>>>>>> > /usr/bin/ld: cannot find -l-lavformat
>>>>>> > /usr/bin/ld: cannot find -l-lavcodec
>>>>>> > /usr/bin/ld: cannot find -l-lavutil
>>>>>> > /usr/bin/ld: cannot find -l-lswscale
>>>>>> > /usr/bin/ld: cannot find -l-lbz2
>>>>>> >
>>>>>> > And this is really killing me. I have been trying to solve this for
>>>>>> days.
>>>>>> >
>>>>>> > Thank you in advance.
>>>>>>
>>>>>> _______________________________________________
>>>>>> Libav-user mailing list
>>>>>> Libav-user at ffmpeg.org
>>>>>> http://ffmpeg.org/mailman/listinfo/libav-user
>>>>>>
>>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Libav-user mailing list
>>>>> Libav-user at ffmpeg.org
>>>>> http://ffmpeg.org/mailman/listinfo/libav-user
>>>>>
>>>>>
>>>>
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>>>>
>>>>
>>>
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>>>
>>
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