Unable to connect to Websphere MQ Manager using XMS

Question

This code reproduces the issue:

#include <iostream>
#include <xms.hpp>

int main()
{
    try
    {
        xms::ConnectionFactory factory;

        factory.setIntProperty(XMSC_CONNECTION_TYPE,      XMSC_CT_WMQ);
        factory.setIntProperty(XMSC_WMQ_CONNECTION_MODE,  XMSC_WMQ_CM_CLIENT);
        factory.setStringProperty(XMSC_WMQ_QUEUE_MANAGER, "my.queue.manager");
        factory.setStringProperty(XMSC_WMQ_HOST_NAME,     "my.dev.mq");
        factory.setStringProperty(XMSC_WMQ_CHANNEL,       "my.channel");
        factory.setIntProperty(XMSC_WMQ_PORT,              1414);

         std::cout << "Is Factory Null? => " << factory.isNull() << std::endl;
         xms::Connection conn = factory.createConnection(); //THIS THROWS EXCEPTION
         std::cout << "Is Factory Null? => " << factory.isNull() << std::endl;
    }
    catch(xms::Exception const & e)
    {
         e.dump(std::cout);
    }
}

It throws exception, dumping the following message:

Is Factory Null? => 0
Exception:
ErrorData =
ErrorCode = 26 (XMS_E_CONNECT_FAILED)
JMS Type  = 1 (XMS_X_GENERAL_EXCEPTION)
Linked Exception:
ErrorData = libmqic_r.so
ErrorCode = 0 (XMS_E_NONE)
JMS Type  = 1 (XMS_X_GENERAL_EXCEPTION)

Any idea what is wrong with the code?

Note that devpmmq is just an alias to the actual IP address (host). If I put any random/nonsense value for it, I get the same error, which is bad because the API should have given a better error message such as "host not found" or something alone that line. Is there any way to enable more verbose diagnostics?

score 1 · Accepted Answer · answered May 27 '14 at 11:01

1

XMS C/C++ internally loads WebSphere MQ client libraries. The problem here is that XMS is unable to find WebSphere MQ client library libmqm_r.so.

What is puzzling me is that the code has set XMSC_WMQ_CONNECTION_MODE as XMSC_WMQ_CM_CLIENT but XMS is attempting to load libmqm_r.so. It should have attempted to load libmqic_r.so.

Have you installed WebSphere MQ client? Also what is the version of XMSClients can be downloaded from here.

answered May 27 '14 at 11:01

Shashi

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Thanks a lot. Now its working (all I had to set the LD_LIBRARY_PATH pointing to the directory which contains `libmqic_r.so`). And you're right, it should have been `libmqic_r.so`. It was a typo (I was experimenting with different values, and in that process I posted mismatched error). – Nawaz May 27 '14 at 11:25
Could you please provide me with a link to online doc which explains which `*.so` are for what purpose. I mean, how would I know whether I need `libmqm.so` or `libmqm_r.so` or any other `.so` for that matter. What is the difference between them? and so on. – Nawaz Jan 28 '15 at 11:21
1

Have a look at this link: http://www-01.ibm.com/support/knowledgecenter/SSFKSJ_7.5.0/com.ibm.mq.dev.doc/q028460_.htm – Shashi Jan 28 '15 at 14:18
I've written a distributed application using XMS. When I run this, using valgrind, it reports `Invalid free()/delete/delete[]`. So I wrote tiny producer-consumer program to reproduce this error, and I found that when this tiny program is linked against `libmqic_r.so`, only then it reports `Invalid free()/delete/delete[]`. My tiny program does NOT use anything or call any function from XMS. Just linking against `libmqic_r.so` is enough to produce the error. Could you please give me some pointers/guesses what might have gone wrong? – Nawaz Jan 29 '15 at 12:55
... the stacktrace reported by valgrind contains these two interesting functions: `exit` from `libc` and `_vgnU_freeres` from `vg_preloaded.so`. It seems when the program exits and the library unloads, it tries to deallocate some memory, this `Invalid free...` error appears. – Nawaz Jan 29 '15 at 12:56
Does your program terminates with an error or is it that Valgrind is showing that and application does not end with an error? If the case is former, then I would suggest a PMR/Ticket with IBM. – Shashi Jan 30 '15 at 04:23
The tiny program doesn't terminates an error. It is just that Valgrind says there is `Invalid free` showing the stacktrace. However, the real program ends up with a mutex-lock failure, with the error code `EINVAL` which, as per [the doc](http://pubs.opengroup.org/onlinepubs/007908799/xsh/pthread_mutex_lock.html), means either 1) *the calling thread's priority is higher than the mutex's current priority ceiling*, or 2) *"mutex does not refer to an initialised mutex object."* . – Nawaz Jan 30 '15 at 09:59
.... The latter case could mean there is memory-corruption, as per [this](http://stackoverflow.com/questions/7651501/boost-lock-guardboostmutex-throws-einval-exception) answer, which also suggests to use valgrind. And valgrind indeed shows Invalid free. – Nawaz Jan 30 '15 at 10:00

Unable to connect to Websphere MQ Manager using XMS

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