win: Work towards getting 'minidump' to compile

compat/win/sys/types.h

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
 #ifndef CRASHPAD_COMPAT_WIN_SYS_TYPES_H_
 #define CRASHPAD_COMPAT_WIN_SYS_TYPES_H_
 
 // This is intended to be roughly equivalent to #include_next.
 #include <../include/sys/types.h>
 
 #ifdef _WIN64
 typedef __int64 ssize_t;
 #else
-typedef _W64 int ssize_t;

[Mark Mentovai, 2015/02/02 22:10:28]

I thought _W64 sounded correct for this when you added it. It matched the
declaration of size_t from the SDK. No good?

[scottmg, 2015/02/02 22:31:45]

Yeah, it does, I was just trying to avoid the need to include another header
here (windows.h) which could be confusing from sys/types.h.

Instead, I should have switched to __w64, which I've done now. Ref:
https://msdn.microsoft.com/en-us/library/s04b5w00.aspx

[Mark Mentovai, 2015/02/02 22:57:21]

scottmg wrote:
How does this work when _W64 didn’t? It looks like _W64 can only be __w64 or
blank.

[scottmg, 2015/02/02 23:16:37]

That's right. __w64 is compiler defined, not by any header. _W64 is the Windows
SDK wrapper around that to avoid having to #if every time, but since we're
already doing that to change the size of the type, _W64 will always be __w64
here.

[Mark Mentovai, 2015/02/02 23:32:08]

Right, my point is:

1. _W64 was always __w64 for us.

2. Something was broken and you removed _W64 to unbreak it.

3. Later, you switched this to __w64, and it remained unbroken.

But given (1), how is (3) any different than what we had before?

[scottmg, 2015/02/03 18:12:56]

Sorry, my explanations were too terse.

The original problem was that this header was incorrect -- it didn't #include
<windows.h>, so _W64 was only available sometimes by accident. But as it
happened, windows.h was always included before this file in all of our
translation units before this CL.

One fix would be to leave it as _W64 and include windows.h here. But that seems
heavy, since we know the value of _W64 will always be __w64 in this case.

[Mark Mentovai, 2015/02/03 18:26:32]

Got it! Thanks for the explanation.

+typedef int ssize_t;
 #endif
 
+typedef unsigned long pid_t;
+
 #endif  // CRASHPAD_COMPAT_WIN_SYS_TYPES_H_