You need the following C/C++ libraries to build flowWorkspace from source (using Rtools for windows users).
-- libxml2

Linux users
These libraries are installed in non-standard locations, please pass their 'prefix' to the configure script. e.g.
R CMD INSTALL flowWorkspace/ --configure-args='--with-xml=/home/yourname/xml_dir'

Also make sure these libraries can be found by R at run-time by adding them to LD_LIBRARY_PATH environment variable. e.g.
 export LD_LIBRARY_PATH=/home/yourname/xml_dir:$LD_LIBRARY_PATH
Add this to your `~/.profile` file can avoid doing so next time.

Windows users

To install libxml2:

1. Download the pre-built binary from

2. unzip it (e.g. to c:\libxml2)
and you should see the directory structure like below in both i386 and x64 folder
   |-----libxml (all *.h are here)
   |-lib (we should have static libary libxml2.a here)
3. set up the environment variable LIB_XML2 in order for flowWorkspace to find its library files and header files.  
You can do this by:
 * right click "Computer" and select "Properties"
 * click "Advanced system settings" and select "Advanced" tab
 * click the "Environment Variables"  button and bring up the dialog box
 * click the "New" button and enter "LIB_XML2" in the "Variable name" field, and /path/to/your/libxml2 (e.g. c:/libxml2) in the "Variable value" field. 
  Remember to use "/" instead of "\" as the directory delimiter.

You can download Rtools at which provides the resources for building R and R packages. You should add to the Path variable the paths to the various components of Rtools. Please read the "Windows Toolset" appendix at for more details.