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FNWRITE macro

The FNWRITE macro provides the declaration for the application-defined callback function to write data to a file in an FDI context.

Syntax

C++
Copy 

void FNWRITE(
  [in] INT_PTR  hf,
  [in] void FAR *pv[bcount(cb)],
       UINT     cb
);

Parameters

hf [in]

An application-defined value used to identify the open file.

pv [in]

Pointer to the buffer containing the data to be written.

cb

The maximum number of bytes to be written.

Return value

The indicated callback function returns the number of bytes written. However, a value of -1 indicates an error.

Remarks

The function accepts parameters similar to _write.

Examples

C++
Copy 

FNWRITE(fnFileWrite)
{
    DWORD dwBytesWritten = 0;

    if ( WriteFile((HANDLE)hf, pv, cb, &dwBytesWritten, NULL) == FALSE )
    {
        dwBytesWritten = (DWORD)-1;
    }

    return dwBytesWritten;
}

Requirements

Header
Fdi.h

See also

FDICreate

 

 

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