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QueryDosDevice info  Overview  Group

The QueryDosDevice function lets an application obtain information about MS-DOS device names. The function can obtain the current mapping for a particular MS-DOS device name. The function can also obtain a list of all existing MS-DOS device names.

MS-DOS device names are stored as symbolic links in the Windows NT object name space. The code that converts an MS-DOS path into a corresponding Windows NT path uses these symbolic links to map MS-DOS devices and drive letters. The QueryDosDevice function provides a mechanism whereby a Win32-based application can query the names of the symbolic links used to implement the MS-DOS device namespace as well as the value of each specific symbolic link.

DWORD QueryDosDevice(

    LPCTSTR lpDeviceName,

// address of MS-DOS device name string

    LPTSTR lpTargetPath,

// address of buffer for storing query results

    DWORD ucchMax 

// maximum storage capacity of buffer



Pointer to an MS-DOS device name string specifying the target of the query.

This parameter can be NULL. In that case, the QueryDosDevice function will store a list of all existing MS-DOS device names into the buffer pointed to by lpTargetPath.

Pointer to a buffer that will receive the result of the query. The function fills this buffer with one or more null-terminated strings. The final null-terminated string is followed by an additional NULL.

If lpDeviceName is non-NULL, the function obtains information about the particular MS-DOS device specified by lpDeviceName. The first null-terminated string stored into the buffer is the current mapping for the device. The other null-terminated strings represent undeleted prior mappings for the device.

If lpDeviceName is NULL, the function obtains a list of all existing MS-DOS device names. Each null-terminated string stored into the buffer is the name of an existing MS-DOS device.

Specifies the maximum number of characters that can be stored into the buffer pointed to by lpTargetPath.

Return Values

If the function succeeds, the return value is the number of characters stored into the buffer pointed to by lpTargetPath.

If the function fails, the return value is zero. To get extended error information, call GetLastError.


The DefineDosDevice function provides a means whereby a Win32-based application can create and modify the symbolic links used to implement the MS-DOS device namespace.

MS-DOS device names are global. Once defined, an MS-DOS device name remains visible to all processes until either it is explicity removed or the system reboots.

See Also


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