wiocp.cpp

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#include "precompiled.h"
#include "lib/sysdep/os/win/wiocp.h"

#include "lib/file/file.h"  // ERR::IO
#include "lib/sysdep/os/win/wutil.h"


void AttachToCompletionPort(HANDLE hFile, HANDLE& hIOCP, ULONG_PTR key, DWORD numConcurrentThreads)
{
    WinScopedPreserveLastError s;   // CreateIoCompletionPort

    // (when called for the first time, ends up creating hIOCP)
    hIOCP = CreateIoCompletionPort(hFile, hIOCP, key, numConcurrentThreads);
    ENSURE(wutil_IsValidHandle(hIOCP));
}


Status PollCompletionPort(HANDLE hIOCP, DWORD timeout, DWORD& bytesTransferred, ULONG_PTR& key, OVERLAPPED*& ovl)
{
    if(hIOCP == 0)
        return ERR::INVALID_HANDLE; // NOWARN (happens if called before the first Attach)

    WinScopedPreserveLastError s;

    bytesTransferred = 0;
    key = 0;
    ovl = 0;
    if(GetQueuedCompletionStatus(hIOCP, &bytesTransferred, &key, &ovl, timeout))
        return INFO::OK;
    const Status ret = StatusFromWin();
    if(ret == ERR::AGAIN || ret == ERR::ABORTED)    // avoid polluting last error
        SetLastError(0);
    return ret; // NOWARN (let caller decide what to do)
}