StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
primarykey
Id
5500630
data
AcceptedAnswerId
0
AnswerCount
0
ClosedDate
CommentCount
0
CommunityOwnedDate
CreationDate
2011-03-31T13:28:29.107
FavoriteCount
0
LastActivityDate
2011-03-31T13:28:29.107
LastEditDate
LastEditorUserId
0
OwnerUserId
9073
ParentId
3130785
PostTypeId
2
Score
2
ViewCount
0
LastEditorDisplayName
text
Body
There will be an IO completion item queued for an IO operation whenever the IO operation is able to start. Regardless of whether an error is encountered or not after the IO operation starts, a completion item will be queued to the completion port. There is a mapping problem between the <code>NTSTATUS</code> codes returned by the IO system and Win32 error codes that makes it hard to tell what statuses are errors and which are just informational. <code>NTSTATUS</code>, which is used by the kernel and the native API, has four levels of severity: success, information, warning and error. Anything but an error code would indicate that the IO operation was able to start. Win32 only has one severity (<code>ERROR_*</code>), so the success, information and warning codes had to be mapped alongside the error codes. <ul> <li><code>ERROR_IO_PENDING</code> - <code>STATUS_PENDING</code> is a success status</li> <li><code>ERROR_MORE_DATA</code> - <code>STATUS_BUFFER_OVERFLOW</code> a warning or <code>STATUS_MORE_ENTRIES</code> a success status</li> </ul> You can ignore any non-error codes that ReadFile or WriteFile return and expect a queued completion item, but determining which is which can be a bit of a pain. It would be nice if the Win32 error codes were better organized, but Microsoft does provide a mapping from <code>NTSTATUS</code> to Win32 error codes: <a href="http://support.microsoft.com/kb/113996" rel="nofollow">http://support.microsoft.com/kb/113996</a>. See <code>ntstatus.h</code> in the platform SDK or your VS installation to determine what severity a <code>NTSTATUS</code> code is. It is possible for the IO operation to be completed when the original API call returns, e.g. a read request that was just copied out of the cache (nothing to wait on asynchronously). A completion message will still be queued in such cases for consistency's sake.
Tags
Title
singulars
PostAcceptedAnswerId
1. This table or related slice is empty.
PostParentId
1. POWhen are IO completion port packets sent and when not?
 singulars
 PostTypePostTypeId
 PTQuestion
PostTypePostTypeId
1. PTAnswer
UserLastEditorUserId
1. This table or related slice is empty.
UserOwnerUserId
1. USChris Smith
plurals
PostLinksPostIdRelatedPostId
1. This table or related slice is empty.
PostLinksRelatedPostIdPostId
1. This table or related slice is empty.
PostsAcceptedAnswerId
1. POWhen are IO completion port packets sent and when not?
 singulars
 PostTypePostTypeId
 PTQuestion
PostsParentIdCreationDate
1. This table or related slice is empty.
VotesPostIdCreationDate
1. VO
 singulars
 PostPostId
 PO
 UserUserId
 This table or related slice is empty.
 VoteTypeVoteTypeId
 VTAcceptedByOriginator
2. VO
 singulars
 PostPostId
 PO
 UserUserId
 This table or related slice is empty.
 VoteTypeVoteTypeId
 VTUpMod
CommentsPostId
1. This table or related slice is empty.

Querying!

Guidance

A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.