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Message
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| fil |
 Posted: Mon Jan 15, 2007 12:17 am Post subject: Message format problem |
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Newbie
Joined: 12 Jan 2007
Posts: 3
Location: Germany
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I have written a MQ application some years ago (MQ 5.3, DEC Alpha
TRU64 UNIX, Perl-based) for sending an receiving messages. For test
purposes I'm used a C++ application (same version and platform)
simulating the other side of communication.
Now I "ported" the MQ application to a Linux x86 platform (MQ 6.0.0.0, RedHat 3).
While testing the communication against the old simulator I got following
problem on simulator side:
Getting the message from the Queue results in an "Non-text message" error.
Afterwards I uses IBMs sample applications (amqsget0.c and imqsget.cpp) as simulator
with following effect:
With amqsget0 the message can read (MQGET) from the queue,
but using imqsget I got the same error.
The only modification in amqsget0 was to extend the buffer size
(avoiding Reason Code 2080).
In imqsget I have added following four lines just after getting the
message (and also resized the buffer):
| Code: |
char buffer[ 800 + 1 ]; /* Message buffer */
/* ...*/
if ( queue.get( msg, gmo ) ) {
int iDataLength = msg.dataLength(); /* 1 */
printf("message of length %d received\n", iDataLength); /* 2 */
buffer[ msg.dataLength( ) ] = 0 ; /* 3 */
printf( "message <%s>\n", msg.bufferPointer( ) ); /* 4 */
/**************************************************************/
/* Display each message received */
/**************************************************************/
if ( msg.formatIs( MQFMT_STRING ) ) {
buffer[ msg.dataLength( ) ] = 0 ; /* add terminator */
printf( "message <%s>\n", msg.bufferPointer( ) );
} else {
printf( "Non-text message\n" );
}
} else {
/* ... */
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The output of both additional printf's [2,4] are identical to output from amqsget0 (what I expect).
Nevertheless the format check "if ( msg.formatIs( MQFMT_STRING ) ) {" goes into the else branch,
"Non-text message".
I can't see any difference between amqsget0 and imqsget resulting into the problem described.
Any help would be great, thanks.
Frank |
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| jefflowrey |
| Posted: Mon Jan 15, 2007 3:13 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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First off, the constant MQFMT_STRING might be declared as MQC.MQFMT_STRING or etc. in the C++ environment - you should double-check the Using C/C++ manual to see what it says about constants.
Second, it could be that the message really doesn't have Format = MQFMT_STRING. You should use amqsbcg or amqsbcgc to look at the message on the queue and see what the format and the data actually are.
_________________
I am *not* the model of the modern major general. |
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| fil |
| Posted: Mon Jan 15, 2007 6:29 am Post subject: |
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Newbie
Joined: 12 Jan 2007
Posts: 3
Location: Germany
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Hi,
The MQC.MQFMT_STRING is defined as "MQSTR ", and
MQC.MQFMT_NONE as " " (8 spaces).
I have repeated the test on both environments (DEC Alpha - DEC Alpha
and Linux - DEC Alpha) and printed the messages using amqsbcg:
1. Test DEC Alpha - DEC Alpha
Sender:
| Code: |
Format : 'MQXMIT '
/*...*/
00000080: 2202 0000 3303 0000 4D51 5354 5220 2020 '"...3...MQSTR ' |
Receiver:
2. Test Linux - DEC Alpha
Sender:
| Code: |
Format : 'MQXMIT '
/* ... */
00000080: 2202 0000 3303 0000 2020 2020 2020 2020 '"...3... ' |
Receiver:
The difference I have found is that the MQFMT string was not written into the message (on Linux).
I think this would causes the problem I have.
Do you have any idea about the reason?
Thanks
Frank. |
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| Vitor |
| Posted: Mon Jan 15, 2007 6:34 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| fil wrote: |
Do you have any idea about the reason?
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In the Linux example, the putting application isn't setting it?
_________________
Honesty is the best policy.
Insanity is the best defence. |
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| jefflowrey |
| Posted: Mon Jan 15, 2007 6:35 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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What I meant was that your code might have to say "MQC.MQFMT_STRING", rather than just "MQFMT_STRING" in order to get the right constant value.
Also, yes, if the Format field does not contain a Format of "MQSTR ", then the message won't be treated as string data.
So that *is* your problem, and you need to figure out why.
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I am *not* the model of the modern major general. |
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| fjb_saper |
| Posted: Mon Jan 15, 2007 6:56 am Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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and you really want to use MQC.MQFMT_STRING because the variable format is fixed string 8 char long which does not match "MQSTR" !
Enjoy 
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MQ & Broker admin |
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| fil |
| Posted: Tue Jan 16, 2007 3:01 am Post subject: |
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Newbie
Joined: 12 Jan 2007
Posts: 3
Location: Germany
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Yes, the usage of the constant MQC.MQFMT_STRING was incorrect.
We using a Perl wrapper for the MQ libraries, so it tooks a
while to find out the right place for a correction
(and how to solve it).
But now everything works fine.
Many thanks for your help.
Frank. |
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