我正在使用重叠IO来同时读取和编写C代码中的单个Windows管道。我想编写一个同步函数来从单独的线程读取和写入数据。如果您使用的是同步IO,则无法同时读取和写入管道。我的客户端和我的服务器使用相同的写/读功能。我的客户端一次又一次地发送服务器从未接收过的数据。有谁知道这会怎么样?如果我在客户端使用同步IO,一切都按预期工作。
服务器管道由以下cmd打开:
CreateNamedPipe(pipeName, PIPE_ACCESS_DUPLEX | FILE_FLAG_OVERLAPPED, PIPE_TYPE_BYTE | PIPE_READMODE_BYTE | PIPE_WAIT,
instances, PIPE_BUF_SIZE, PIPE_BUF_SIZE, 0, NULL);
客户端管道以这种方式打开:
CreateFile(pipeName, GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL);
我正在使用这些读取功能:
int readBytesPipeCommChannel(PipeCommChannelData* comm, uint32_t* amount)
OVERLAPPED osRead;
memset(&osRead, 0, sizeof(osRead));
osRead.hEvent = comm->readAsyncIOEvent;
int err = 0;
if(!ReadFile(comm->pipeH, comm->receiveBuffer, sizeof(comm->receiveBuffer), amount, &osRead))
{
err = GetLastError();
if (err == ERROR_IO_PENDING)
{
if(WaitForSingleObject(osRead.hEvent, INFINITE))
{
GetOverlappedResult(comm->pipeH, &osRead, amount, TRUE);
}
else
{
CancelIo(comm->pipeH);
return PIPE_EVENT_ERROR;
}
}
else if(err != ERROR_BROKEN_PIPE)
{
return PIPE_READ_ERROR;
}
}
if(err == ERROR_BROKEN_PIPE)
return PIPE_BROKEN_ERR;
return PIPE_OK;
}
最后但并非最不重要的是写函数:
int sendBytesPipeCommChannel(PipeCommChannelData* comm, const uint8_t* bytes, uint32_t amount)
{
OVERLAPPED osWrite;
memset(&osWrite, 0, sizeof(osWrite));
osWrite.hEvent = comm->writeAsyncIOEvent;
uint32_t bytesWritten = 0;
for(uint32_t curPos = 0; curPos < amount; curPos += bytesWritten)
{
if(!WriteFile(comm->pipeH, &bytes[curPos], (amount - curPos), &bytesWritten, &osWrite))
{
if (GetLastError() != ERROR_IO_PENDING)
return PIPE_WRITE_ERR;
if(!WaitForSingleObject(osWrite.hEvent, INFINITE))
{
CancelIo(comm->pipeH);
return PIPE_EVENT_ERROR;
}
}
}
return PIPE_OK;
}
答案 0 :(得分:0)
ReadFile的文档说:
如果使用
hFile
打开FILE_FLAG_OVERLAPPED
,则以下条件有效:
lpNumberOfBytesRead
参数应设置为NULL
。使用GetOverlappedResult
函数获取读取的实际字节数。
即使操作同步完成,这也适用。