Nothing works - Jump to declaration, auto completion etc

[MartinChekurov]

My vim and clang are both 32 bit.
I am using python 2.7.
I have set correctly the path to clang:
let g:clang_library_path='C:/Program Files (x86)/LLVM/bin'
I have set correctly that i want to use compile_commands.json:
let g:clang_use_library = 1
That's all my clang configuration in _vimrc.
When i open a .c file i get no errors.
Also i have compile_commands.json file.
But none of the features of the plugin works...I don't know why.
Jump to declaration - C-] doesn't work.
C-W C-U for autocomplete - Pattern not found