VL_COMPILE() uses MEX() to compile VLFeat MEX files. This command works only under Windows and is used to re-build problematic binaries. The preferred method of compiling VLFeat on both UNIX and Windows is through the provided Makefiles.
VL_COMPILE() only compiles the MEX files and assumes that the VLFeat DLL (i.e. the file VLFEATROOT/bin/win{32,64}/vl.dll) has already been built. This file is built by the Makefiles.
By default VL_COMPILE() assumes that Visual C++ is the active MATLAB compiler. VL_COMPILE('lcc') assumes that the active compiler is LCC instead (see MEX -SETUP). Unfortunately LCC does not seem to be able to compile the latest versions of VLFeat due to bugs in the support of 64-bit integers. Therefore it is recommended to use Visual C++ instead.
See also: VL_NOPREFIX(), VL_HELP().