On Wednesday, 14 December 2022 at 11:30:07 UTC, Vitaliy Fadeev
wrote:
Hi! I open a device under Windows:
```
HANDLE h = CreateFileW( ... );
```
in procedure:
```
HANDLE open_keyboard_device2( LPCWSTR path, int* error_number )
{
...
HANDLE dev_handle =
CreateFileW(
path,
0,
FILE_SHARE_READ | FILE_SHARE_WRITE,
NULL,
OPEN_EXISTING,
0,
NULL
);
...
return dev_handle;
}
```
and I want to close HANDLE automatically, when **dev_handle**
destroyed by GC:
```
CloseHandle( h );
```
How to do it?
How to define HANDLE var ? What to return from procedure? How
to call CloseHandle( h ) when variable destroyed?
I was trying **std.typecons.Unique**. But where I must put
**CloseHandle( h )** ?
I was trying **std.typecons.Unique** with custom class
**SafeHabdle**
```
class SafeHandle
{
HANDLE h;
this( HANDLE h )
{
this.h = h;
}
~this()
{
if ( h != INVALID_HANDLE_VALUE )
CloseHandle( h );
}
}
```
and using it:
```
Unique!SafeHandle open_keyboard_device2( LPCWSTR path, int*
error_number )
{
...
Unique!SafeHandle dev_handle =
new SafeHandle(
CreateFileW(
path,
0,
FILE_SHARE_READ | FILE_SHARE_WRITE,
NULL,
OPEN_EXISTING,
0,
NULL
)
);
...
}
```
It complex. Because needed:
```
Unique!SafeHandle open_keyboard_device2( LPCWSTR path, int*
error_number )
Unique!SafeHandle dev_handle = new SafeHandle( CreateFileW(
... ) );
DeviceIoControl( dev_handle.h, ...);
```
vs
```
HANDLE open_keyboard_device2( LPCWSTR path, int*
error_number )
HANDLE dev_handle = CreateFileW( ... );
DeviceIoControl( dev_handle, ...);
```
Last is readable.
Teach me the most beautiful way.
How to make beautiful?
Thanks!
The most beautiful way is any high-level language. What you seem
to lack is developing your engineering skills, something most of
us begin doing in elementary schooling.
