class & function names highlighting in Vim

I had this very same problem when I started using vim. The solution is simple, you just have to edit the c syntax file used by vim, here's how to do it:

When you start editing a C or C++ file, vim reads the default c syntax file located in

$VIMRUNTIME/syntax/c.vim

(Where $VIMRUNTIME is where you have vim installed. You can find out it's default value by opening vim and using the command ":echo $VIMRUNTIME").

You can simply overwrite that file, or you can create your custom C syntax file (which will be loaded by vim instead of the default one) in this location:

$HOME/.vim/syntax/c.vim      (for UNIX)
$HOME/vimfiles/syntax/c.vim  (for PC or OS/2)

(I have never used a Mac so I don't know which one will work for you. You can find out more in the vim help, ":help vimfiles")

Now the fun part. Copy the default "$VIMRUNTIME/syntax/c.vim" file to your vimfiles directory ("$HOME/.vim/syntax/c.vim" for UNIX), and edit it by adding these lines:

" Highlight Class and Function names
syn match    cCustomParen    "(" contains=cParen,cCppParen
syn match    cCustomFunc     "\w\+\s*(" contains=cCustomParen
syn match    cCustomScope    "::"
syn match    cCustomClass    "\w\+\s*::" contains=cCustomScope

hi def link cCustomFunc  Function
hi def link cCustomClass Function

That's it! Now functions and class names will be highlighted with the color defined in the "Function" highlight (":hi Function"). If you want to customize colors, you can change the last two lines above to something like this:

hi def cCustomFunc  gui=bold guifg=yellowgreen
hi def cCustomClass gui=reverse guifg=#00FF00

or you can leave the C syntax file alone and define colors in your vimrc file (":help vimrc"):

hi cCustomFunc  gui=bold guifg=yellowgreen
hi cCustomClass gui=reverse guifg=#00FF00

(Note the absence of the "def" keyword, go to ":help highlight-default" for details). For the available parameters to the ":hi" command see ":help :highlight".

You can find the complete c.vim file for Vim 7.2 on this link (Note: only use this if you have a non-modified Vim, version 7.2):

http://pastebin.com/f33aeab77

And the obligatory screenshot:

this is my first post here and i didn't know how to make an observation, the answer of Eduardo makes "(" and "{" look unmached and bugs syntax foldind, I changed it a little to fix this.

syn match    cCustomParen    "?=(" contains=cParen,cCppParen
syn match    cCustomFunc     "\w\+\s*(\@=" contains=cCustomParen
syn match    cCustomScope    "::"
syn match    cCustomClass    "\w\+\s*::" contains=cCustomScope
hi def cCustomFunc  gui=bold guifg=yellowgreen
hi def link cCustomClass Function