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POg++ Linking Error on Mac while compiling FFMPEG
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copied!<p>g++ on Snow Leopard is throwing linking errors on the following piece of code</p> <p>test.cpp</p> <pre><code>#include <iostream> using namespace std; #include <libavcodec/avcodec.h> // required headers #include <libavformat/avformat.h> int main(int argc, char**argv) { av_register_all(); // offending library call return 0; } </code></pre> <p>When I try to compile this using the following command</p> <pre><code>g++ test.cpp -I/usr/local/include -L/usr/local/lib \ -lavcodec -lavformat -lavutil -lz -lm -o test </code></pre> <p>I get the error Undefined symbols: "av_register_all()", referenced from: _main in ccUD1ueX.o ld: symbol(s) not found collect2: ld returned 1 exit status</p> <p>Interestingly, if I have an equivalent c code, test.c</p> <pre><code>#include <stdio.h> #include <libavcodec/avcodec.h> #include <libavformat/avformat.h> int main(int argc, char**argv) { av_register_all(); return 0; } </code></pre> <p>gcc compiles it just fine</p> <pre><code>gcc test.c -I/usr/local/include -L/usr/local/lib \ -lavcodec -lavformat -lavutil -lz -lm -o test </code></pre> <p>I am using Mac OS X 10.6.5</p> <pre><code>$ g++ --version i686-apple-darwin10-g++-4.2.1 (GCC) 4.2.1 (Apple Inc. build 5664) $ gcc --version i686-apple-darwin10-gcc-4.2.1 (GCC) 4.2.1 (Apple Inc. build 5664) </code></pre> <p>FFMPEG's libavcodec, libavformat etc. are C libraries and I have built them on my machine like thus:</p> <pre><code>./configure --enable-gpl --enable-pthreads --enable-shared \ --disable-doc --enable-libx264 make && sudo make install </code></pre> <p>As one would expect, libavformat indeed contains the symbol av_register_all</p> <pre><code>$ nm /usr/local/lib/libavformat.a | grep av_register_all 0000000000000000 T _av_register_all 00000000000089b0 S _av_register_all.eh </code></pre> <p>I am inclined to believe g++ and gcc have different views of the libraries on my machine. g++ is not able to pick up the right libraries. Any clue?</p>

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