Youcompleteme: YCM doesn't list anything in the global namespace when prefixed with ::

[drtwox]

In C++ it is valid to prefix names in the global namespace with ::, yet YCM doesn't support this. For example: If using the OpenGL C interface the exported functions are available in the global namespace and may be used like so:

glEnable(...) OR ::glEnable(...). YCM offers to complete for the first, but not the (more correct!) second.

[Valloric]

In C++ it is valid to prefix names in the global namespace with ::, yet YCM doesn't support this.

It does. You have somehow misconfigured YCM. You're probably using incorrect flags in your ycm_extra_conf.py file.

[drtwox]

Sorry for this incorrect issue report then! Is this a suitable place to work out WHY it's not working for me? Here's my ycm_extra_conf.py file:

import os
import ycm_core

# CHANGE THIS LIST OF FLAGS. YES, THIS IS THE DROID YOU HAVE BEEN LOOKING FOR.
flags = [
'-Wall',
'-Wextra',
'-Werror',
'-Wpedantic',
'-DNDEBUG',
'-DUSE_CLANG_COMPLETER',
'-std=c++11',
'-x',
'c++',

# C++ headers on my Linux machine
'-isystem',
'/usr/include/c++/4.7.3/',

# C++ headers on my Windows machine
'-isystem',
'C:/Program Files (x86)/Microsoft Visual Studio 12.0/VC/include',

# Windows external include directories
'-isystem',
'./external/windows/glew-1.10.0/include',
'-isystem',
'./external/windows/glfw-3.0.2.bin.WIN32/include/',
'-isystem',
'./external/windows/glm-0.9.4.6/',
'-isystem',
'./external/windows/libogg-1.3.1/include/',
'-isystem',
'./external/windows/libvorbis-1.3.3/include/',
'-isystem',
'./external/windows/lpng166/',
'-isystem',
'./external/windows/openal-soft-1.15.1-bin/include',
'-isystem',
'./external/windows/zlib-1.2.8/',

# Linux extern include directory
'-isystem',
'./external/linux/include',

# Boost
'-isystem',
'C:/Boost/include/boost-1_55',
'-isystem',
'/usr/local/include/boost/',

# Project libraries
'-I',
'./archive/include',
'-I',
'./event/include',
'-I',
'./gl/include',
'-I',
'./image/include',
'-I',
'./job/include',
'-I',
'./log/include',
'-I',
'./system/include',
'-I',
'./vfs/include'
]

# Set this to the absolute path to the folder (NOT the file!) containing the
# compile_commands.json file to use that instead of 'flags'. See here for
# more details: http://clang.llvm.org/docs/JSONCompilationDatabase.html
#
# Most projects will NOT need to set this to anything; you can just change the
# 'flags' list of compilation flags. Notice that YCM itself uses that approach.
compilation_database_folder = ''

if compilation_database_folder:
  database = ycm_core.CompilationDatabase( compilation_database_folder )
else:
  database = None


def DirectoryOfThisScript():
  return os.path.dirname( os.path.abspath( __file__ ) )


def MakeRelativePathsInFlagsAbsolute( flags, working_directory ):
  if not working_directory:
    return list( flags )
  new_flags = []
  make_next_absolute = False
  path_flags = [ '-isystem', '-I', '-iquote', '--sysroot=' ]
  for flag in flags:
    new_flag = flag

    if make_next_absolute:
      make_next_absolute = False
      if not flag.startswith( '/' ):
        new_flag = os.path.join( working_directory, flag )

    for path_flag in path_flags:
      if flag == path_flag:
        make_next_absolute = True
        break

      if flag.startswith( path_flag ):
        path = flag[ len( path_flag ): ]
        new_flag = path_flag + os.path.join( working_directory, path )
        break

    if new_flag:
      new_flags.append( new_flag )
  return new_flags


def FlagsForFile( filename ):
  if database:
    # Bear in mind that compilation_info.compiler_flags_ does NOT return a
    # python list, but a "list-like" StringVec object
    compilation_info = database.GetCompilationInfoForFile( filename )
    final_flags = MakeRelativePathsInFlagsAbsolute(
      compilation_info.compiler_flags_,
      compilation_info.compiler_working_dir_ )

    # NOTE: This is just for YouCompleteMe; it's highly likely that your project
    # does NOT need to remove the stdlib flag. DO NOT USE THIS IN YOUR
    # ycm_extra_conf IF YOU'RE NOT 100% YOU NEED IT.
    try:
      final_flags.remove( '-stdlib=libc++' )
    except ValueError:
      pass
  else:
    relative_to = DirectoryOfThisScript()
    final_flags = MakeRelativePathsInFlagsAbsolute( flags, relative_to )

  return {
    'flags': final_flags,
    'do_cache': True
  }

[Valloric]

Your flags appear to be fine. You might also have an error in the file you are trying to complete in which is making Clang bork on ::.

I honestly don't know. What I do know is that :: at the top level works (just tried it), so it's not a YCM bug.

[drtwox]

I checked my .vimrc and noticed I was still loading tag files for the different libraries my project uses. I commented them out, restarted vim, and the YCM completion works as expected.

[Valloric]

Now that is weird. Why would tags files impact how semantic completion works?

[MacroHongJian]

@drtwox you can see this add this to your vimrc

let g:ycm_semantic_triggers =  {
  \   'c' : ['->', '.','re![_a-zA-z0-9]'],
  \   'objc' : ['->', '.', 're!\[[_a-zA-Z]+\w*\s', 're!^\s*[^\W\d]\w*\s',
  \             're!\[.*\]\s'],
  \   'ocaml' : ['.', '#'],
  \   'cpp,objcpp' : ['->', '.', '::','re![_a-zA-Z0-9]'],
  \   'perl' : ['->'],
  \   'php' : ['->', '::'],
  \   'cs,java,javascript,typescript,d,python,perl6,scala,vb,elixir,go' : ['.'],
  \   'ruby' : ['.', '::'],
  \   'lua' : ['.', ':'],
  \   'erlang' : [':'],
  \ }

[codercodingthecode]

:point_up: that should be in the docs if it is not. But this completely solved my problem of not having auto-completion in C.