[Ffmpeg-user] Problem using libraries with MSVC++

I have compiled the libraries using cygwin. I am trying to use them in an MSVC++ app. I always get the following message. error LNK2019: unresolved external symbol "int __cdecl av_fifo_init(struct AVFifoBuffer *,int)" (?av_fifo_init@@YAHPAUAVFifoBuffer@@H at Z) referenced in function "public: virtual long __thiscall CFFStream::Init(struct UrlInfo *)" (?Init at CFFStream@@UAEJPAUUrlInfo@@@Z) A few other functions are not found but all have to do with av_fifo_xxxx. I have tried to recompile the libraries with mingw and I get exaclty the same message. I have inspected the avutil.lib and the functions are there. Does anybody have any idea what the problem/solution may be? Rafael