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This call returns information for a specific file.
Syntax
DosQFileInfo (FileHandle, FileInfoLevel, FileInfoBuf, FileInfoBufSize)
Parameters
;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.
Return Code
rc (USHORT) - return
Return code descriptions are:
* 0 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)
Example Code
C Binding
<PRE> typedef struct _FDATE { /* fdate */
unsigned day : 5; /* binary day for directory entry */
unsigned month : 4; /* binary month for directory entry */ unsigned year : 7; /* binary year for directory entry */
} FDATE;
typedef struct _FTIME { /* ftime */
unsigned twosecs : 5; /* binary number of two-second increments */
unsigned minutes : 6; /* binary number of minutes */ unsigned hours : 5; /* binary number of hours */
} FTIME;
typedef struct _FILESTATUS { /* fsts */
FDATE fdateCreation; /* date of file creation */
FTIME ftimeCreation; /* time of file creation */ FDATE fdateLastAccess; /* date of last access */ FTIME ftimeLastAccess; /* time of last access */ FDATE fdateLastWrite; /* date of last write */ FTIME ftimeLastWrite; /* time of last write */ ULONG cbFile; /* file size (end of data) */ ULONG cbFileAlloc; /* file allocated size */ USHORT attrFile; /* attributes of the file */
} FILESTATUS;
typedef struct _GEA { /* gea */
BYTE cbName; /* name length not including NULL */
CHAR szName[1]; /* attribute name */
} GEA;
typedef struct _GEALIST { /* geal */
ULONG cbList; /* total bytes of structure including full list */
GEA list[1]; /* variable length GEA structures */
} GEALIST;
typedef struct _FEA { /* fea */
BYTE fEA; /* flags */
BYTE cbName; /* name length not including NULL */ USHORT cbValue; /* value length */
} FEA;
typedef struct _FEALIST { /* feal */
ULONG cbList; /* total bytes of structure including full list */
FEA list[1]; /* variable length FEA structures */
} FEALIST;
typedef struct _EAOP { /* eaop */
PGEALIST fpGEAList; /* general EA list */
PFEALIST fpFEAList; /* full EA list */ ULONG oError;
} EAOP;
#define INCL_DOSFILEMGR
USHORT rc = DosQFileInfo(FileHandle, FileInfoLevel, FileInfoBuf,
FileInfoBufSize);
HFILE FileHandle; /* File handle */ USHORT FileInfoLevel; /* File data required */ PBYTE FileInfoBuf; /* File data buffer (returned) */ USHORT FileInfoBufSize; /* File data buffer size */
USHORT rc; /* return code */
</PRE>
MASM Binding
<PRE> FDATE struc
fdate_fs dw ?
FDATE ends
FTIME struc
ftime_fs dw ?
FTIME ends
FILESTATUS struc
fsts_fdateCreation dw (size FDATE)/2 dup (?) ;date of file creation
fsts_ftimeCreation dw (size FTIME)/2 dup (?) ;time of file creation fsts_fdateLastAccess dw (size FDATE)/2 dup (?) ;date of last access fsts_ftimeLastAccess dw (size FTIME)/2 dup (?) ;time of last access fsts_fdateLastWrite dw (size FDATE)/2 dup (?) ;date of last write fsts_ftimeLastWrite dw (size FTIME)/2 dup (?) ;time of last write fsts_cbFile dd ? ;file size (end of data) fsts_cbFileAlloc dd ? ;file allocated size fsts_attrFile dw ? ;attributes of the file
FILESTATUS ends
GEA struc
gea_cbName db ? ;name length not including NULL
gea_szName db 1 dup (?) ;attribute name
GEA ends
GEALIST struc
geal_cbList dd ? ;total bytes of structure including full list
geal_list db size GEA * 1 dup (?) ;variable length GEA structures
GEALIST ends
FEA struc
fea_fEA db ? ;flags
fea_cbName db ? ;name length not including NULL fea_cbValue dw ? ;value length
FEA ends
FEALIST struc
feal_cbList dd ? ;total bytes of structure including full list
feal_list db size FEA * 1 dup (?) ;variable length FEA structures
FEALIST ends
EAOP struc
eaop_fpGEAList dd ? ;general EA list
eaop_fpFEAList dd ? ;full EA list eaop_oError dd ? ;
EAOP ends
EXTRN DosQFileInfo:FAR INCL_DOSFILEMGR EQU 1
PUSH WORD FileHandle ;File handle PUSH WORD FileInfoLevel ;File data required PUSH@ OTHER FileInfoBuf ;File data buffer (returned) PUSH WORD FileInfoBufSize ;File data buffer size CALL DosQFileInfo
Returns WORD </PRE>
Note
Text based on http://www.edm2.com/index.php/DosQFileInfo