DosQueryQueue (OS/2 1.x)

Description

This call determines the number of elements in a queue.

Syntax

 DosQueryQueue

    (QueueHandle, NumberElements)

Parameters

QueueHandle (HQUEUE) - input 

Handle of the queue to find size.

NumberElements (PUSHORT) - output 

Address of the number of entries in the queue waiting to be processed.

Return Code

rc (USHORT) - return

Return code descriptions are:

• 0 NO_ERROR
• 337 ERROR_QUE_INVALID_HANDLE

Remarks

Any thread of a process that has access to the queue (because of a DosCreateQueue or a DosOpenQueue request) may issue DosQueryQueue to determine the number of elements currently in the queue.

If the process that created the queue closes it before this request is issued, ERROR_QUE_INVALID_HANDLE is returned.

Example Code

C Binding

#define INCL_DOSQUEUES

USHORT  rc = DosQueryQueue(QueueHandle, NumberElements);

HQUEUE           QueueHandle;    /* Queue handle */
PUSHORT          NumberElements; /* Size of the queue (returned) */

USHORT           rc;             /* return code */

MASM Binding

EXTRN  DosQueryQueue:FAR
INCL_DOSQUEUES      EQU 1

PUSH   WORD    QueueHandle    ;Queue handle
PUSH@  WORD    NumberElements ;Size of the queue (returned)
CALL   DosQueryQueue

Returns WORD