Changeset 21493 in vbox for trunk/include

Timestamp:

Jul 10, 2009 7:58:31 PM (16 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

49940

Message:

Runtime/File: Add flag to disable the file cache

File:

• trunk/include/iprt/file.h (modified) (2 diffs)

trunk/include/iprt/file.h

@@ -149 +149 @@
  */
 #define RTFILE_O_ASYNC_IO           0x00040000
+/** Disables caching of the opened file on the host.
+ * Useful when using very big files which might
+ * bring the host I/O scheduler to its knees
+ * during high I/O load.
+ * @remark  This flag might impose restrictions
+ *          on the buffer alignment, start offset and/or transfer size.
+ *          On Linux the buffer needs to be aligned to the 512 sector
+ *          boundary.
+ *          On Windows the FILE_FLAG_NO_BUFFERING is used
+ *          (see here for more details
+ *          http://msdn.microsoft.com/en-us/library/cc644950(VS.85).aspx)
+ *          The buffer address, the transfer size and offset needs to be
+ *          aligned to the sector size of the volume.
+ * @remark  This might not be implemented on all platforms,
+ *          and will be ignored on those.
+ */
+#define RTFILE_O_NO_CACHE      0x00080000
 
 /** Mask of all valid flags.
  * @remark  This doesn't validate the access mode properly.
  */
-#define RTFILE_O_VALID_MASK          0x1ff7FB73
+#define RTFILE_O_VALID_MASK          0x1ffFFB73
 
 /** @} */
@@ -1075 +1092 @@
  *
  * @returns IPRT status code.
+ * @returns VERR_FILE_AIO_INSUFFICIENT_RESSOURCES if the maximum number of
+ *          simultaneous outstanding requests would be exceeded.
  *
  * @param   hAioCtx         The async I/O context handle.