Hi Lukasz, I do pass the CMAKE_CXX_FLAGS from ROOT to it. I am using the ExternalProject like this: ExternalProject_Add( XROOTD URL http://xrootd.org/download/v${xrootd_version}/xrootd-${xrootd_version}.tar.gz INSTALL_DIR ${CMAKE_BINARY_DIR} CMAKE_ARGS -DCMAKE_INSTALL_PREFIX:PATH=<INSTALL_DIR> -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER} -DCMAKE_C_FLAGS=${CMAKE_C_FLAGS} -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER} -DCMAKE_CXX_FLAGS=${CMAKE_CXX_FLAGS} ) This produces the following configuration command: cmake -DCMAKE_INSTALL_PREFIX:PATH=/Users/mato/Development/ROOT/root.master -DCMAKE_C_COMPILER=/Users/mato/Development/clang “-DCMAKE_C_FLAGS= -m64 -pipe -W -Wall -fsigned-char -fno-common -Qunused-arguments" -DCMAKE_CXX_COMPILER=/Users/mato/Development/clang++ "-DCMAKE_CXX_FLAGS= -m64 -pipe -W -Wall -Woverloaded-virtual -fsigned-char -fno-common -Qunused-arguments -stdlib=libc++" "-GUnix Makefiles" /Users/mato/Development/ROOT/root.master/XROOTD-prefix/src/XROOTD Cheers, Pere On 14 Mar 2014, at 16:44, Lukasz Janyst <[log in to unmask]<mailto:[log in to unmask]>> wrote: Do you pass extra CXXFLAGS? — Reply to this email directly or view it on GitHub<https://github.com/xrootd/xrootd/issues/96#issuecomment-37662085>. ------------------------------------------------------------- Pere Mato CERN, PH Department, CH 1211 Geneva 23, Switzerland e-mail: [log in to unmask]<mailto:[log in to unmask]> tel: +41 22 76 78696 fax: +41 22 76 68792 gsm: +41 76 48 70855 --- Reply to this email directly or view it on GitHub: https://github.com/xrootd/xrootd/issues/96#issuecomment-37664755 ######################################################################## Use REPLY-ALL to reply to list To unsubscribe from the XROOTD-DEV list, click the following link: https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=XROOTD-DEV&A=1