Cannot get thread ID with Thread.getThis() in specific callback functions on Windows

[Denis Koroskin]

On Mon, 06 Dec 2010 06:38:40 +0300, Haruki Shigemori  
<rayerd.wiz at gmail.com> wrote:

> Hi.
> I cannot get thread ID with Thread.getThis() in specific callback
> functions on Windows.
> What is the cause of this problem?
>
> import win32.windows;
> import win32.mmsystem;
> import std.stdio;
> import core.thread;
>
> extern (Windows)
> void waveInProc(in HWAVEIN handle, in uint message, in DWORD instance,
> in DWORD param1, in DWORD param2)
> {
>         auto tid = Thread.getThis();
>         assert(tid); // tid is null
> }
>
> void main()
> {
>         WAVEFORMATEX formatEx;
>         with (formatEx)
>         {
>                 wFormatTag = WAVE_FORMAT_PCM;
>                 nChannels = 1;
>                 nSamplesPerSec = 44100;
>                 wBitsPerSample = 16;
>                 nBlockAlign = cast(ushort)(wBitsPerSample * nChannels /  
> 8);
>                 nAvgBytesPerSec = nSamplesPerSec * nBlockAlign;
>         }
>
>         HWAVEIN handle;
>         waveInOpen(&handle, WAVE_MAPPER, cast(WAVEFORMATEX*)&formatEx,
> cast(DWORD)&waveInProc, cast(DWORD)null, CALLBACK_FUNCTION);
>
>         uint bufferSize = cast(uint)(formatEx.nAvgBytesPerSec *
> 1/+second+/);
>         WAVEHDR* hdr = new WAVEHDR;
>         hdr.lpData = cast(LPSTR)new ushort[bufferSize];
>         hdr.dwBufferLength = bufferSize;
>         hdr.dwFlags = 0;
>         hdr.dwLoops = 0;
>
>         waveInPrepareHeader(handle, hdr, WAVEHDR.sizeof);
>         waveInAddBuffer(handle, hdr, WAVEHDR.sizeof);
>         waveInStart(handle);
>
>         readln();
> }

Because D runtime doesn't know about the newly created thread, and static  
constructors weren't called. Try calling the following in your callbacks:

if (Thread.getThis() is null) thread_attachThis(); // if  
(dont_know_about_this_thread) initialize_it();