Hi all, Thanks for your helps. First of all, I am actually super duper new in linux things and cross compiling, so frankly I don't understand about all things that I did, including also the commands for compiler and configure. I gathered all those by searching internet and reading some forums and just "try and error". My final goal is to compile ginac so that I have *.lib (static) or *.dll (shared) in to use in MSVC. That what brought me to that website link. I tried to follow all the steps with correction necessary according to my situation. As far as understand, CC=cl CXX=cl CCAS=cl is necessary if we want to compile library with cl.exe (microsoft compiler and linker), of course CC = cl shows that intention. I dont understand for the remaining two. That is the reason I put those options in configure. As said previously, missing in installing libreadline make error in ginsh compiling process. I am aware of that issue. However, (as i asked initially) I just dont get it when it is said that ginsh will not be compiled but in fact it is being compiled. I finally managed this problem by manually edit the makefile. I erased ginsh doc tool option in SUBDIRS = ginac check ginsh tools doc DIST_SUBDIRS = ginac check ginsh tools doc becoming SUBDIRS = ginac check DIST_SUBDIRS = ginac check then ginac is compiled succesfully. All tests are passed too. Now, I get the *.lib, I tested it in visual studio, It works well in release mode but not in debug. I dont know why. I am also trying to make *.dll. It is succesfully compiled, but all tests are failed. Again, I dont know what is the reason. related to Jan's suggestion about putting in .ll ( is it ginsh_lexer.ll ??), it is failed. Same error appeared. #ifdef _MSC_VER #define YY_NO_UNISTD_H #endif about alex Here is my setting : environment : msys (MinGW) compiler : cl ginac : ginac-1.6.2 cln : cln-1.3.2 gmp : gmp-5.0.5 XP ~ chris ~