#71 Dynamic linking and globbing for MSVC

[Doug Cook]

The ZIP file includes hand-crafted project files for building SoX under MSVC9 and Windows-compatible implementations of glob and ltdl. Designed to work with the current CVS sources. The project files could probably be replaced with CMAKE with a bit of work, but the glob and ltdl are new and are not currently available via CMAKE. The resulting sox.exe has support for all SoX features except magic, ffmpeg, amr, and pulseaudio. LAME (libmp3lame.dll or lame_enc.dll), MAD (libmad.dll or cygmad-0.dll) and libsndfile (libsndfile-1.dll) are loaded at runtime if they are available.

How to build:
1. Check out the SoX CVS code into a directory named sox.
2. Extract the source code for the other libraries next to the sox directory. Remove the version numbers from the directory names.
-- flac-1.2.1.tar.gz extracted into directory flac
-- lame-398-2.tar.gz extracted into directory lame
-- libid3tag-0.15.1b.tar.gz extracted into directory libid3tag
-- libmad-0.15.0b.tar.gz extracted into directory libmad
-- libogg-1.1.4.tar.gz extracted into directory libogg
-- libpng-1.2.39-no-config.tar.gz extracted into directory libpng
-- libvorbis-1.2.3.tar.gz extracted into directory libvorbis
-- wavpack-4.50.1.tar.gz extracted into directory wavpack
-- zlib-1.2.3.tar.gz extracted into directory zlib
3. Install libsndfile from http://www.mega-nerd.com/libsndfile/libsndfile-1.0.20-w32-setup.exe.
4. Copy the folder C:\Program Files\Mega-Nerd\libsndfile to create libsndfile next to your other libraries. (Only the header file is needed to compile, but the DLL is needed at runtime if you want to use libsndfile support, and the build steps include copying the DLL to the output directory.)
5. Extract the msvc9.zip file into the SoX directory (i.e. so that you have sox\msvc9, but not sox\msvc9\msvc9).
6. Open the sox\msvc9\SoX.sln solution and build.
7. The resulting executable files will be in sox\msvc9\Debug or sox\msvc9\Release. The resulting sox.exe will dynamically link to libmp3lame.dll, libmad.dll, and libsndfile-1.dll if they are available, but will run without them (though the corresponding features will be unavailable if they are not present).

Points to note:
- The included libsox project enables OpenMP support. You can disable this in the libsox project properties under Configuration Properties, C/C++, Language, OpenMP support. If you don't disable it, you will need vcomp90.dll and Microsoft.VC90.OpenMP.manifest either installed on your machine or copied into the directory next to sox.exe. If you have OpenMP support in your copy of Visual Studio, these files can be found here: c:\Program Files\Microsoft Visual Studio 9.0\vc\redist\x86\Microsoft.VC90.OPENMP. Note that some editions of Visual Studio might not include OpenMP support.
- The included projects enable SSE2. You can disable this in the project properties under Configuration Properties, C/C++, Code Generation, Enable Enhanced Instruction Set. Note that some editions of Visual Studio might not include Enhanced Instruction Set support.
- The included projects set the floating-point model to "fast". This means that the compiler is free to optimize floating-point operations. For example, the compiler might optimize the expression (14.0 * x / 7.0) into (x * 2.0). In addition, the compiler is allowed to use 80-bit floating-point registers to store temporary values (instead of rounding each intermediate result to a 32-bit or 64-bit value. In some cases, these optimizations can change the results of floating-point calculations. If you run into trouble, you can change the settings to one of the other values. "precise" avoids any optimization that might change the result but keeps optimizations that might give more accurate results (such as using 80-bit temporary register values). "strict" avoids any optimization that might change the result and rounds every intermediate result to the requested precision. You can change this setting in the project properties under Configuration Properties, C/C++, Code Generation, Floating Point Model.

[Doug Cook]