DosQFSAttach

Bindings:  C, MASM 

Query information about an attached file system (local or remote), or 
about a character device or pseudo-character device attached to the file 
system. 

 DosQFSAttach     (DeviceName, Ordinal, FSAInfoLevel, DataBuffer, 
                  DataBufferLen, Reserved) 
 

 DeviceName (PSZ) - input 
    Address of a drive letter or the name of a character or 
    pseudo-character device. If DeviceName is a drive, it is an ASCIIZ 
    string having the form of drive letter followed by a colon. If 
    DeviceName is a character or pseudo-character device name, its format 
    is that of an ASCIIZ string in the format of an OS/2 file name in a 
    subdirectory called \DEV\. This parameter is ignored if level 2 or 3 
    is specified for FSAInfoLevel. 

 Ordinal (USHORT) - output 
    Index into the list of character or pseudo-character devices, or the 
    set of drives.  Ordinal always starts at 1.  The Ordinal position of 
    an item in a list has no significance at all.  Ordinal is used 
    strictly to step through the list.  The mapping from Ordinal to item 
    is volatile and may change from one call to DosQFSAttach to the next. 
    This parameter is ignored if level 1 is specified for FSAInfoLevel. 

 FSAInfoLevel (USHORT) - input 
    Level of information returned in DataBuffer: 

    o Level 0001H returns data for the specific drive or device name 
      referred to by DeviceName.  The Ordinal field is ignored. 

    o Level 0002H returns data for the entry in the list of character or 
      pseudo-character devices selected by Ordinal. The DeviceName field 
      is ignored. 

    o Level 0003H returns data for the entry in the list of drives 
      selected by Ordinal. The DeviceName field is ignored. 

 DataBuffer (PBYTE) - output 
    Address of the return information buffer, has the following format: 

    iType (USHORT) 
       Type of item. 

       Value     Definition 
       1         Resident character device 
       2         Pseudo-character device 
       3         Local drive 
       4         Remote drive attached to FSD. 

    cbName (USHORT) 
       Length of item name, not counting null. 

    szName (UCHAR) 
       Item name, ASCIIZ string. 

    cbFSDName (USHORT) 
       Length of FSD name, not counting null. 

    szFSDName (UCHAR) 
       Name of FSD item is attached to, ASCIIZ string. 

    cbFSAData (USHORT) 
       Length of FSD Attach data returned by FSD. 

    rgFSAData (UCHAR) 
       FSD Attach data returned by FSD. 

 Note: 
    The szFSDName is the FSD name exported by the FSD, which is not 
    necessarily the same as the FSD name in the boot sector. 

   
    For local character devices (iType = 1), cbFSDName = 0 and szFSDName 
    contains only a terminating NULL byte, and cbFSAData = 0. 

   
    For local drives (iType = 3), szFSDName contains the name of the FSD 
    attached to the drive at the time of the call.  This information 
    changes dynamically.  If the drive is attached to the kernel's 
    resident file system, szFSDName contains FAT or unknown. Since the 
    resident file system gets attached to any disk that other FSDs refuse 
    to mount, it is possible to have a disk that does not contain a 
    recognizable file system, but yet gets attached to the resident file 
    system.  In this case, it is possible to detect the difference, and 
    this information would help programs in not destroying data on a disk 
    that was not properly recognized. 

 DataBufferLen (PUSHSHORT) - input/output 
    Address of the byte length of the return buffer.  Upon return, it is 
    the length of the data returned in DataBuffer by the FSD.  This field 
    must be initialized. 

 Reserved (ULONG) - input 
    Reserved, must be set to zero. 

 rc (USHORT) - return 
    Return code descriptions are: 

    0         NO_ERROR 
    15        ERROR_INVALID_DRIVE 
    111       ERROR_BUFFER_OVERFLOW 
    124       ERROR_INVALID_LEVEL 
    259       ERROR_NO_MORE_ITEMS 
 
 Remarks 

 Information about all block devices and all character and 
 pseudo-character devices is returned by this call. 

 The information returned by this call is highly volatile.  Calling 
 programs should be aware that the returned information may have already 
 changed by the time it's returned to them. 

 The information returned for disks that are attached to the kernel's 
 resident file system can be used to determine if the kernel definitely 
 recognized the disk as one with its file system on it, or if the kernel 
 just attached its file  system to it because no other FSDs mounted the 
 disk. This can be important information for a program that needs to know 
 what  file system is attached to the drive.  It is quite easy to get into 
 a situation where the FSD that recognizes a certain disk has not been 
 installed into the system.  In such a case, there is a potential for the 
 data on the disk to be destroyed since the wrong file system is attached 
 to the disk by default.