(FAQ) What are AS/400 Data Queue APIs?

Data queues are a type of system object that you can create, to which one high-level language (HLL) program can send data, and from which another HLL program can receive data. The receiving program can be waiting for the data, or can receive the data later.

Before using a data queue, you must first create it using the Create Data Queue (CRTDTAQ) command.

The data queue APIs are:

* Clear Data Queue (QCLRDTAQ) clears all entries from a data queue.


Required Parameter Group:

1 Data queue name Input Char(10)
2 Library name Input Char(10)

Optional Parameter Group:

3 Key order Input Char(2)
4 Length of key data Input Packed(3,0)
5 Key data Input Char(*)
6 Error code I/O Char(*)

Default Public Authority: *USE


* Receive Data Queue (QRCVDTAQ) receives data from the specified data queue.

Required Parameter Group:

1 Data queue name Input Char(10)
2 Library name Input Char(10)
3 Length of data Output Packed(5,0)
4 Data Output Char(*)
5 Wait time Input Packed(5,0)

Optional Parameter Group 1:

6 Key order Input Char(2)
7 Length of key data Input Packed(3,0)
8 Key data I/O Char(*)
9 Length of sender information Input Packed(3,0)
10 Sender information Output Char(*)

Optional Parameter Group 2:

11 Remove message Input Char(10)
12 Size of data receiver Input Packed(5,0)
13 Error code I/O Char(*)

Default Public Authority: *USE

* Retrieve Data Queue Description (QMHQRDQD) retrieves information about a data queue.

Required Parameter Group:

1 Receiver variable Output Char(*)
2 Length of receiver variable Input Binary(4)
3 Format name Input Char(8)
4 Qualified data queue name Input Char(20)

Default Public Authority: *USE

Threadsafe: Yes

* Retrieve Data Queue Message (QMHRDQM) retrieves an entry from a data queue without removing the entry.

Required Parameter Group:

1 Receiver variable Output Char(*)
2 Length of receiver variable Input Binary(4)
3 Format name Input Char(8)
4 Qualified data queue name Input Char(20)
5 Message selection information Input Char(*)
6 Length of message selection information Input Binary(4)
7 Message selection information format name Input Char(8)
8 Error code I/O Char(*)

Default Public Authority: *USE

Threadsafe: Yes

* Send to a Data Queue (QSNDDTAQ) sends data to the specified data queue.

Required Parameter Group:

1 Data queue name Input Char(10)
2 Library name Input Char(10)
3 Length of data Input Packed(5,0)
4 Data Input Char(*)

Optional Parameter Group 1:

5 Length of key data Input Packed(3,0)
6 Key data Input Char(*)

Optional Parameter Group 2:

7 Asynchronous request Input Char(10)

Optional Parameter Group 3:

8 Data is from a journal entry Input Char(10)

Default Public Authority: *USE

Threadsafe: Conditional