DosQFileInfo

This call returns information for a specific file.

DosQFileInfo

(FileHandle, FileInfoLevel, FileInfoBuf, FileInfoBufSize)

FileHandle (HFILE) - input

File handle.
FileInfoLevel (USHORT) - input
Level of file information required. A value of 1, 2, or 3 can be specified. Level 4 is reserved. The structures described in FileInfoBuf indicate the information returned for each of these levels.
FileInfoBuf (PBYTE) - output
Address of the storage area where the system returns the requested level of file information. File information, where applicable, is at least as accurate as the most recent DosClose, DosBufReset, DosSetFileInfo, or DosSetPathInfo.

Level 1 Information

FileInfoBuf contains the following structure, to which file information is returned:

filedate (FDATE)

Structure containing the date of file creation.

Bit

Description
15-9
Year, in binary, of file creation
8-5
Month, in binary, of file creation
4-0
Day, in binary, of file creation.
filetime (FTIME)
Structure containing the time of file creation.

Bit

Description
15-11
Hours, in binary, of file creation
10-5
Minutes, in binary, of file creation
4-0
Seconds, in binary number of two-second increments, of file creation.
fileaccessdate (FDATE)
Structure containing the date of last access. See FDATE in filedate.
fileaccesstime (FTIME)
Structure containing the time of last access. See FTIME in filetime.
writeaccessdate (FDATE)
Structure containing the date of last write. See FDATE in filedate.
writeaccesstime (FTIME)
Structure containing the time of last write. See FTIME in filetime.
filesize (ULONG)
File size.
filealloc (ULONG)
Allocated file size.
fileattrib (USHORT)
Attributes of the file, defined in DosSetFileMode.
Level 2 Information
FileInfoBuf contains a structure similar to the Level 1 structure, with the addition of the cbList field after the fileattrib field.

cbList (ULONG)

On output, this field contains the length of the entire EA set for the file object. This value can be used to calculate the size of the buffer required to hold EA information returned when FileInfoLevel = 3 is specified.
Level 3 Information
FileInfoBuf contains an EAOP structure, which has the following format:

fpGEAList (PGEALIST)

Address of GEAList. GEAList is a packed array of variable length "get EA" structures, each containing an EA name and the length of the name.
fpFEAList (PFEALIST)
Address of FEAList. FEAList is a packed array of variable length "full EA" structures, each containing an EA name and its corresponding value, as well as the lengths of the name and the value.
oError (ULONG)
Offset into structure where error has occurred.

On input, FileInfoBuf is an EAOP structure. fpGEAList points to a GEA list defining the attribute names whose values are returned. fpFEAList points to a data area where the relevant FEA list is returned. The length field of this FEA list is valid, giving the size of the FEA list buffer. oError points to the offending GEA entry in case of error. Following is the format of the GEAList structure:

cbList (ULONG)
Length of the GEA list, including the length itself.
list (GEA)
List of GEA structures. A GEA structure has the following format:

cbName (BYTE)

Length of EA ASCIIZ name, which does not include the null character.
szName (CHAR)
ASCIIZ name of EA.

On output, FileInfoBuf is unchanged. The buffer pointed to by fpFEAList is filled in with the returned information. If the buffer fpFEAList points to isn't large enough to hold the returned information (ERROR_BUFFER_OVERFLOW) cbList is still valid, assuming there's at least enough space for it. Its value is the size of the entire EA set for the file, even though only a subset of attributes was requested. Following is the format of the FEAList structure:

cbList (ULONG)
Length of the FEA list, including the length itself.
list (FEA)
List of FEA structures. An FEA structure has the following format:

Flags (BYTE)

Bit indicator describing the characteristics of the EA being defined.

Bit

Description
7
Critical EA.
6-0
Reserved and must be set to zero.
If bit 7 is set to 1, this indicates a critical EA. If bit 7 is 0, this means the EA is noncritical; that is, the EA is not essential to the intended use by an application of the file with which it is associated.
cbName (BYTE)
Length of EA ASCIIZ name, which does not include the null character.
cbValue (USHORT)
Length of EA value, which cannot exceed 64KB.
szName (PSZ)
Address of the ASCIIZ name of EA.
aValue (PSZ)
Address of the free-format value of EA.

Note: The szName and aValue fields are not included as part of header or include files. Because of their variable lengths, these entries must be built manually.

FileInfoBufSize (USHORT) - output

Length of FileInfoBuf.
rc (USHORT) - return
Return code descriptions are:
• NO_ERROR 5
  ERROR_ACCESS_DENIED
  6
  ERROR_INVALID_HANDLE
  111
  ERROR_BUFFER_OVERFLOW
  124
  ERROR_INVALID_LEVEL
  130
  ERROR_DIRECT_ACCESS_HANDLE
  254
  ERROR_INVALID_EA_NAME
  255
  ERROR_EA_LIST_INCONSISTENT
  Remarks

  The FAT file system supports modification of only date and time information contained in file information level 1. Zero is returned for the creation and access dates and times.

  To return information contained in any of the file information levels, DosQFileInfo has to be able to read the open file. DosQFileInfo works only when the file is opened for read access, with a deny-write sharing mode specified for access by other processes. If the file is already opened by another process that has specified conflicting sharing and access modes, a call to DosOpen or DosOpen2 fails.

  DosEnumAttribute returns the lengths of EAs. This information can be used to calculate the size of FileInfoBuf needed to hold full extended attribute (FEA) information returned by DosQFileInfo when Level 3 is specified. The size of the buffer is calculated as follows:

  One byte (for fea_usFlags) +
  One byte (for fea_cbName) +
  Two bytes (for fea_cbValue) +
  Value of cbName (for the name of the EA) +
  One byte (for terminating NULL in fea_cbName) +
  Value of cbValue (for the value of the EA)
  

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