Questions and postings pertaining to the usage of ImageMagick regardless of the interface. This includes the command-line utilities, as well as the C and C++ APIs. Usage questions are like "How do I use ImageMagick to create drop shadows?".
Use MagickLib::LogColorspace to avoid the undeclared identifier error. We have a patch in ImageMagick 6.2.4 Beta available by tomorrow to fix this problem.
You should be able to work directly in the log colorspace. ImageMagick normally does not convert colorspaces until the image is written and the format requires a specific colorspace (which is typically RGB). If you want the full range of colors, in.colorspace(RGBColorspace), should work.
Recent versions of ImageMagick will not convert from Log to RGB if you set the ImageInfo structure colorspace member to something other than the default of undefined. Set it to LogColorspace and you should be fine. You will recall a few algorithms will convert to RGB if it makes sense.