Fixes this bug:

    Omni completion takes the wrong structure for variable arguments.  (Bill
    McCarthy, 2007 Feb 18)

The text is quite unclear but luckily the mail archives remember -- see this
thread:  http://marc.info/?t=117182868600002&r=1&w=2

The following code demonstrates the problem:

    typedef struct A
    {
        int a1;
        int a2;
        int a3;
    } A;

    typedef struct B
    {
        int b1;
        int b2;
        int b3;
    } B;

    void myfunc(A *a, B *b)
    {
        b->    /* Typing <ctrl-x><ctrl-o> here will make Vim suggest
                  elements from structure A. */
    }

The script for C omni completion cannot handle multiple variable declarations
on the same line.  This patch puts in the necessary handling for multiple
variable declarations on the same line.  First, if the line contains a
semicolon before the variable name, the last semicolon before the name is found
and everything preceding it on the line, including itself, is removed.  This
leaves only the relevant declaration for later matching.  Second, if the line
contains a comma before the variable name, the last comma before the name is
found and, if the variable has its type next to it, everything preceding the
comma on the line, including the comma itself, is removed.  This last part
applies to variable declarations inside a function declaration (the situation
demonstrated by the bug report).

The approach is very robust and handles e.g.:

    A a; B b;
    A a, b; B c;
    A a; B b, c;
    A a, b; B c, d;
    void func(A a, B b)
    void func(A a, B b) /* comment */
    void func(A a, B b) // comment
    void func(A a, B b) { /* comment */
    void func(A a, B b) { // comment
    void func(A a, B b, /* comment */
              C c) { /* comment */

It only fails when "searchdecl()" doesn't find the correct row or column for
the declaration.  This typically happens when a comment next to the declaration
mentions the variable's name.

Created by Martin Toft <mt@martintoft.dk> during Google Summer of Code 2007.


Index: runtime/autoload/ccomplete.vim
===================================================================
RCS file: /cvsroot/vim/vim7/runtime/autoload/ccomplete.vim,v
retrieving revision 1.20
diff -c -r1.20 ccomplete.vim
*** runtime/autoload/ccomplete.vim	13 May 2006 09:09:15 -0000	1.20
--- runtime/autoload/ccomplete.vim	30 Aug 2007 00:33:18 -0000
***************
*** 1,7 ****
  " Vim completion script
  " Language:	C
  " Maintainer:	Bram Moolenaar <Bram@vim.org>
! " Last Change:	2006 May 08
  
  
  " This function is used for the 'omnifunc' option.
--- 1,7 ----
  " Vim completion script
  " Language:	C
  " Maintainer:	Bram Moolenaar <Bram@vim.org>
! " Last Change:	2007 Aug 30
  
  
  " This function is used for the 'omnifunc' option.
***************
*** 119,124 ****
--- 119,145 ----
      " TODO: join previous line if it makes sense
      let line = getline('.')
      let col = col('.')
+     if stridx(strpart(line, 0, col), ';') != -1
+       " Handle multiple declarations on the same line.
+       let col2 = col - 1
+       while line[col2] != ';'
+ 	let col2 -= 1
+       endwhile
+       let line = strpart(line, col2 + 1)
+       let col -= col2
+     endif
+     if stridx(strpart(line, 0, col), ',') != -1
+       " Handle multiple declarations on the same line in a function
+       " declaration.
+       let col2 = col - 1
+       while line[col2] != ','
+ 	let col2 -= 1
+       endwhile
+       if strpart(line, col2 + 1, col - col2 - 1) =~ ' *[^ ][^ ]*  *[^ ]'
+ 	let line = strpart(line, col2 + 1)
+ 	let col -= col2
+       endif
+     endif
      if len(items) == 1
        " Completing one word and it's a local variable: May add '[', '.' or
        " '->'.