我一直试图在OSX 10.8上安装ffi
gem install ffi -v '1.1.5'
结果
ERROR: Error installing ffi:
ERROR: Failed to build gem native extension.
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby extconf.rb
checking for ffi.h... no
checking for ffi.h in /usr/local/include,/usr/include/ffi... no
checking for rb_thread_blocking_region()... no
checking for ruby_native_thread_p()... no
checking for rb_thread_call_with_gvl()... no
creating extconf.h
creating Makefile
make
mkdir -p "/Library/Ruby/Gems/1.8/gems/ffi-1.1.5/ext/ffi_c"/libffi-i386; (if [ ! -f "/Library/Ruby/Gems/1.8/gems/ffi-1.1.5/ext/ffi_c"/libffi-i386/Makefile ]; then echo "Configuring libffi for i386"; cd "/Library/Ruby/Gems/1.8/gems/ffi-1.1.5/ext/ffi_c"/libffi-i386 && env CC=" xcrun cc" CFLAGS="-arch i386 " LDFLAGS="-arch i386" "/Library/Ruby/Gems/1.8/gems/ffi-1.1.5/ext/ffi_c/libffi"/configure --disable-static --with-pic=yes --disable-dependency-tracking --host=i386-apple-darwin …有什么区别
.3+.3+.3+.1 == 1
返回false,而
.3+.3+.1+.3 == 1
返回true？这也适用于Python.