DosQueryFHState Parameter - pMode

pMode (PULONG) - output

Address of the contents of the open-mode word defined in a previous DosOpen function.

Bit

Description
15
OPEN_FLAGS_DASD (0x00008000)
Direct Open flag:
• pszFileName field in DosOpen represents a file to be opened normally.

• pszFileName is the "drive:" (such as C: or A:). It represents a mounted disk or diskette volume to be opened for direct access.
14
OPEN_FLAGS_WRITE_THROUGH (0x00004000)
Write-Through flag:
• Write operations to the file go through the file system buffer cache.

• Write operations to the file may go through the file system buffer cache, but the sectors are written (the actual file I/O operation is completed) before a synchronous write call returns. This state of the file defines it as a synchronous file. For synchronous files, this bit is set to 1 because the data must be written to the medium for synchronous write operations.

  The Write-Through flag bit is not inherited by child processes.

13
OPEN_FLAGS_FAIL_ON_ERROR (0x00002000)
Fail-Errors flag. Media I/O errors are handled as follows:
• Reported through the system critical-error handler.
  
• Reported directly to the caller by a return code.

  Media I/O errors generated through Category 08h Logical Disk Control IOCtl Commands always are reported directly to the caller by a return code. The Fail-Errors function applies only to non-IOCtl handle-based file I/O functions.

  The Fail-Errors flag bit is not inherited by child processes.

12
OPEN_FLAGS_NO_CACHE (0x00001000)
Cache or No-Cache:
• The disk driver should place data from I/O operations into the cache on this file.

• I/O operations to the file need not be done through the disk-driver cache.

  The setting of this bit determines whether it is worth caching the data for file-systems drivers and device drivers. This bit, like the Write-Through bit, is a per-handle bit.

  This bit is not inherited by child processes.

11-8
Reserved bits.
7
OPEN_FLAGS_NOINHERIT (0x00000080) Inheritance flag:
• The file handle is inherited by a process that is created by issuing DosExecPgm.

• The file handle is private to the current process.

  This bit is not inherited by child processes.

6-4
Sharing-Mode flags: Define the operations other processes can perform on the file:

001

OPEN_SHARE_DENYREADWRITE
Deny read and write access.
010
OPEN_SHARE_DENYWRITE
Deny write access.
011
OPEN_SHARE_DENYREAD
Deny read access.
100
OPEN_SHARE_DENYNONE
Deny neither read nor write access (deny none).
Any other value is invalid.
3
Reserved.
2-0
Access-Mode flags. File access is assigned as follows:

000

OPEN_ACCESS_READONLY
Read-only access.
001
OPEN_ACCESS_WRITEONLY
Write-only access.
010
OPEN_ACCESS_READWRITE
Read and write access.
Any other value is invalid.

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