Re: VS 2015 support in src/tools/msvc

* Andrew Dunstan wrote:

> On 04/22/2016 01:21 AM, Michael Paquier wrote:

>>>> 5. It also complains about us casting a pid_t to a HANDLE in
>>>> pg_basebackup.c. Not sure what to do about that.
>>> The thing that's being cast is not a PID, but a HANDLE to a process.
>>> pid_t is a typedef for int (in port/win32.h), therefore is always 32
>>> bits, while HANDLE is actually void*. However, Microsoft guarantees
>>> that kernel32 HANDLEs (this includes those to threads and processes)
>>> fit into 32 bits on AMD64.

>> Yes, when casting things this way I think that a comment would be fine
>> in the code. We could do that as separate patches actually.
>
> We are already casting the pid_t to HANDLE and still getting a warning.
> Apparently we need to do something on win64 like
>
> (HANDLE) ((int64) bgchild)

Ah, OK, it warns about a cast to a larger type because the value might
get sign extended. Not unreasonable.

In this case, I would prefer this:

diff --git a/src/include/port/win32.h b/src/include/port/win32.h
index ba8cf9d..b4086f1 100644
--- a/src/include/port/win32.h
+++ b/src/include/port/win32.h
@@ -256,7 +256,7 @@ typedef int gid_t;
typedef long key_t;

#ifdef WIN32_ONLY_COMPILER
-typedef int pid_t;
+typedef intptr_t pid_t;
#endif

/*

With this change, pg_basebackup -X stream works the same when built for
64 and 32 bits.

--
Christian