MySQL Bugs: #32082: Definition of VOID in my_global.h conflicts with windows headers

Bug #32082	Definition of VOID in my_global.h conflicts with windows headers
Submitted:	3 Nov 2007 23:32	Modified:	6 Aug 2008 2:42
Reporter:	Vladislav Vaintroub
Status:	In progress
Category:	Server: Compiling	Severity:	S3 (Non-critical)
Version:	5.0, 5.1, 6.0 (5.2)	OS:	Microsoft Windows
Assigned to:	Davi Arnaut	Target Version:	5.0+
Tags:	Contribution
Triage:	Triaged: D4 (Minor)

Description:
my_global.h defines VOID essentially as
#define VOID(x) x
The intention is to avoid lint warnings about ignored return value of some functions like
printf().The problem however is that this defintion is incompatible with VOID as defined
by Windows SDK headers that come with Visual Studio 8

winnt.h:255
#define VOID void

As a consequence trying to include <windows.h>, if my_global.h is also included will lead
to warning. Trying to include some other windows header e.g dbghelp.h leads to compile
error.

How to repeat:
in mysqld.cc
after
#include "my_global.h"
insert

#ifdef __WIN__
#include <windows.h>
#include <dbghelp.h>
#endif

recompile mysqld.cc, see compiler error

Suggested fix:
-remove the definition of VOID from my_global.h
-replace all occurences of 
VOID(somefunction(someparam)); with (void)somefunction(someparam);

In my understanding (void)myfunc() is quite portable way of telling lint to keep silent
about not checking return code.

patch for 5.2 bk  tree

Attachment: patch.txt (text/plain), 213.27 KiB.

Small correction to the "how to repeat" section
mysqld.cc does not include mysql_global.h directly, but via mysql_priv.h

so test case would be to change

#include "mysql_priv.h"
at the start of the file to

#include "mysql_priv.h"
#ifdef __WIN__
#include <windows.h>
#include <dbghelp.h>
#endif

Thank you for the report.

Verified as described.

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/45053

ChangeSet@1.2571, 2008-04-08 12:30:06+02:00, vvaintroub@wva. +122 -0
  Bug#32082 : definition of VOID in my_global.h conflicts with Windows
  SDK headers
  
  VOID macro is now removed. Its usage is replaced with void cast.
  In some cases, where cast does not make much sense (pthread_*, printf, 
  hash_delete, my_seek), cast is ommited.

Pushed into 6.0.6-alpha