DosMailslotInfo or Dos32MailslotInfo

The DosMailslotInfo API retrieves information about a particular mailslot.

Restrictions

This API can be called from DLS and OS/2 workstations. A call to this API must be issued locally.
Syntax

#include <netcons.h>
#include <mailslot.h>
 
DosMailslotInfo(mailslothandle, pusMessageSize, pusMailslotSize,
               nextsize, nextpriority, msgcount);     /* 16 bit */
 
Dos32MailslotInfo(mailslothandle, pusMessageSize, pusMailslotSize,
               nextsize, nextpriority, msgcount);     /* 32 bit */

Parameters

See Common Parameter Definitions for descriptions of parameters not defined here.

mailslothandle

(unsigned long) specifies (by its handle) the mailslot about which to retrieve information.
pusMessageSize
(16-bit unsigned short LSFAR * or 32-bit unsigned long LSFAR *) points to an unsigned short integer that specifies the maximum size message (in bytes) the mailslot can accept.
pusMailslotSize
(16-bit unsigned short LSFAR * or 32-bit unsigned long LSFAR *) points to an unsigned short integer indicating the size (in bytes) of the mailslot. The value of pusMailslotSize must be equal to or greater than the value of pusMessageSize.
nextsize
(16-bit unsigned short LSFAR * or 32-bit unsigned long LSFAR *) points to an unsigned short integer indicating the size (in bytes) of the next message in the mailslot. If 0, no message is available.
nextpriority
(16-bit unsigned short LSFAR * or 32-bit unsigned long LSFAR *) points to an unsigned short integer indicating the priority (0-9) of the next message in the mailslot. (This parameter is undefined if nextsize is 0.)
msgcount
(16-bit unsigned short LSFAR * or 32-bit unsigned long LSFAR *) points to an unsigned short integer indicating the number of messages the mailslot contains.
Return Codes

The following table lists the return codes most significant to this API. (See API Return Codes for a complete list of return codes.) ┌─────────────────────────────┬────────────┬───────────────────────────────────┐│SYMBOLICCONSTANT │VALUE │MEANING │
├─────────────────────────────┼────────────┼───────────────────────────────────┤
│ NERR_Success │ 0 │ No errors were encountered. │
├─────────────────────────────┼────────────┼───────────────────────────────────┤
│ ERROR_INVALID_HANDLE │ 6 │ The specified handle is not │
│ │ │ valid. │
└─────────────────────────────┴────────────┴───────────────────────────────────┘


Related Information

For information about:

• Creating (and obtaining the handle for) a mailslot, see Mailslot - DosMakeMailslot.

• Writing a message to a mailslot, see Mailslot - DosWriteMailslot.

• Retrieving the most current message in a mailslot, see Mailslot - DosReadMailslot.

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