Microsoft KB Archive/235717

= BUG: CallNamedPipe API lpBytesRead Parameter Returns Bogus Number =

Article ID: 235717

Article Last Modified on 2/12/2007

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APPLIES TO


 * Microsoft Windows 98 Standard Edition, when used with:
 * Microsoft Windows 98 Standard Edition
 * Microsoft Windows 98 Second Edition

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This article was previously published under Q235717



SYMPTOMS
When you use the CallNamedPipe API on Windows 98 to communicate to a message-based Named Pipe on a Windows NT computer, the lpBytesRead parameter which specifies the actual amount of bytes written into the read buffer lpOutBuffer returns a number, which does not reflect the amount of bytes in the buffer. This number is typically a very large number. It should be noted though, that the read buffer will still contain the received data on a successful call.



CAUSE
The SMB used for the named pipe is read incorrectly by Windows 98 for the CallNamedPipe API.



RESOLUTION
If the number of bytes written lpBytesRead into the read buffer is required, a traditional CreateFile/WriteFile/ReadFile sequence of using a named pipe or the TransactNamedPipe API can be used. Alternatively, the following code can be used to mimic the behavior of the CallNamedPipe API: BOOL MimicCallNamedPipe( LPCTSTR lpNamedPipeName,  // pointer to pipe name  LPVOID lpInBuffer,        // pointer to write buffer  DWORD nInBufferSize,      // size, in bytes, of write buffer  LPVOID lpOutBuffer,       // pointer to read buffer  DWORD nOutBufferSize,     // size, in bytes, of read buffer  LPDWORD lpBytesRead,      // pointer to number of bytes read  DWORD nTimeOut            // time-out value, in milliseconds ) { HANDLE hPipe = INVALID_HANDLE_VALUE; DWORD dwPipeMode = PIPE_READMODE_MESSAGE | PIPE_WAIT;

if (WaitNamedPipe(lpNamedPipeName, nTimeOut) == FALSE) return FALSE;

hPipe = CreateFile(lpNamedPipeName, GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL); if (hPipe == INVALID_HANDLE_VALUE) return FALSE; if (SetNamedPipeHandleState(hPipe, &dwPipeMode, NULL, NULL) == FALSE) return FALSE; if (TransactNamedPipe(hPipe, lpInBuffer, nInBufferSize, lpOutBuffer, nOutBufferSize, lpBytesRead, NULL) == FALSE) return FALSE;

CloseHandle(hPipe);

return TRUE; } Microsoft provides programming examples for illustration only, without warranty either expressed or implied, including, but not limited to, the implied warranties of merchantability and/or fitness for a particular purpose. This article assumes that you are familiar with the programming language being demonstrated and the tools used to create and debug procedures. Microsoft support professionals can help explain the functionality of a particular procedure, but they will not modify these examples to provide added functionality or construct procedures to meet your specific needs. If you have limited programming experience, you may want to contact a Microsoft Certified Partner or the Microsoft fee-based consulting line at (800) 936-5200. For more information about Microsoft Certified Partners, please visit the following Microsoft Web site:

https://partner.microsoft.com/global/30000104

For more information about the support options that are available and about how to contact Microsoft, visit the following Microsoft Web site:

http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS



STATUS
Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.

