How to recompile with -fPIC

Question

I was trying to reinstall my ffmpeg  following this guide  on my ARM Ubuntu machine  Unfortunately  when I compile a program which uses this lib I get the following failure    usr bin ld   usr local lib libavcodec a amrnbdec o   relocation R ARM MOVW ABS NC against  a local symbol  can not be used when making a shared object  recompile with -fPIC  usr local lib libavcodec a  could not read symbols  Bad value collect2  ld returned 1 exit status   Now I would like to recompile it with -fPIC like the compiler is suggesting but I have no idea how  Any help is appreciated

User · Answer

After the configure step you probably have a makefile  Inside this makefile look for CFLAGS  or similar   puf -fPIC at the end and run make again  In other words -fPIC is a compiler option that has to be passed to the compiler somewhere

User · Answer

I had this problem when building FFMPEG static libraries  e g  libavcodec a  for Android x86 64 target platform  using Android NDK clang   When statically linking with my library the problem occured although all FFMPEG C -  object files    o  were compiled with -fPIC compile option   x86 64 libavcodec a h264 qpel 10bit o    requires dynamic R X86 64 PC32 reloc against  ff pw 1023   which may overflow at runtime  recompile with -fPIC   The problem occured only for libavcodec a and libswscale a    Source of this problem is that FFMPEG has assembler optimizations for x86  platforms e g  the reported problem cause is in libavcodec h264 qpel 10bit asm -  h264 qpel 10bit o    When producing X86-64 bit static library  e g  libavcodec a  it looks like assembler files  e g  libavcodec h264 qpel 10bit asm  uses some x86  32bit  assembler commands which are incompatible when statically linking with x86-64 bit target library since they don t support required relocation type   Possible solutions    compile all ffmpeg files with no assembler optimizations  for ffmpeg this is configure option  --disable-asm  produce dynamic libraries  e g  libavcodec so  and link them in your final library dynamically   I chose 1  and it solved the problem   Reference  https   tecnocode co uk 2014 10 01 dynamic-relocs-runtime-overflows-and-fpic

User · Answer

Briefly  the error means that you can t use a static library to be linked w  a dynamic one  The correct way is to have a libavcodec compiled into a  so instead of  a  so the other  so library you are trying to build will link well  The shortest way to do so is to add --enable-shared at   configure options  Or even you may try to disable shared  or static  libraries at all    you choose what is suitable for you

User · Answer

In addirion to the good answers here  specifically Robert Lujo s   I want to say in my case I ve been deliberately trying to statically compile a version of ffmpeg  All the required dependencies and what else heretofore required  I ve done static compilation   When I ran   configure for the ffmpeg process I didnt notice --enable-shared was on the commandline  Removing it and running   configure is only then I was able to compile correctly  All 56 mbs of an ffmpeg binary   Check that out as well if your intention is static compilation

User · Answer

I hit this same issue trying to install Dashcast on Centos 7   The fix was adding -fPIC at the end of each of the CFLAGS in the x264 Makefile   Then I had to run make distclean for both x264 and ffmpeg and rebuild

User · Answer

Have a look at this page   you can try globally adding the flag using  export CXXFLAGS   CXXFLAGS -fPIC

User · Answer

Before compiling make sure that  rules mk  file is included properly in Makefile or include it explicitly by    source rules mk

[c++] How to recompile with -fPIC

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