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Message
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| keerthikumar |
 Posted: Mon May 15, 2006 10:35 pm Post subject: Put C structure object into queue |
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Novice
Joined: 23 Nov 2005
Posts: 13
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hello
I want to put a C structure object into queue.
I have the data stored in a C structure object .
What attributes in MQPUT api should i change so that i can send that structure into the queue
thanks and regards |
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| keerthikumar |
| Posted: Mon May 15, 2006 11:24 pm Post subject: |
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Novice
Joined: 23 Nov 2005
Posts: 13
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I tried to use memcpy() function to copy the contents of the struct to unsigned char array but I am not able to copy entire data
so How can i send the entire information of the struct to the queue |
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| Nigelg |
| Posted: Mon May 15, 2006 11:26 pm Post subject: |
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Grand Master
Joined: 02 Aug 2004
Posts: 1046
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In the MQPUT API there are 2 arguments which relate to the data, a char * which is a pointer to the start of the data, and a long which is the length of the data.
Pass your structure to MQPUT by casting a pointer to it to a char *, and set the length to be sizeof your structure.
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| bob_buxton |
| Posted: Tue May 16, 2006 12:45 am Post subject: |
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Master
Joined: 23 Aug 2001
Posts: 266
Location: England
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Does your structure contain any non character data and could your message be sent to a queue manager on a different platfom or to a Java application?
If the answer is yes you will need to consider format conversion.
You would need to invent a format name to put in the MQMD format field and provide a format conversion exit on your receiving system to convert data to the appropriate encoding and code page.
_________________
Bob Buxton
Ex-Websphere MQ Development |
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| keerthikumar |
| Posted: Tue May 16, 2006 1:17 am Post subject: |
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Novice
Joined: 23 Nov 2005
Posts: 13
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yes my structure contains non character data also
struct sAccountDetails
{
char acAccType[10];
double fbalance;
};
struct sPersonalDetails
{
char acCustID[10];
char acCustFirstName[20];
char acCustLastName[20];
char acCustDOB[15];
char acCustAddress[100];
char acCustCity[15];
char acCustPincode[10];
char acCustPhone[12];
};
struct sCustomerDetails
{
struct sPersonalDetails personaldetails;
struct sAccountDetails accountdetails;
}custdetails;
this is my structure.
i tried to do memcpy as
unsigned char buffer[500];
struct sCustomerDetails * temp;
temp=&custdetails;
memcpy(buffer,temp,sizeof(custdetails));
but I could not copy entire structure only custdetails.sPersonalDetails.acCustID was only copied
how should I proceed now |
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| keerthikumar |
| Posted: Tue May 16, 2006 1:25 am Post subject: |
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Novice
Joined: 23 Nov 2005
Posts: 13
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MQMD md = {MQMD_DEFAULT}; /* Message Descriptor */
memcpy(md.Format, /* character string format */
MQFMT_STRING, (size_t)MQ_FORMAT_LENGTH);
This the message format i have chosen
MQPUT(Hcon, /* connection handle */
Hobj, /* object handle */
&md, /* message descriptor */
&pmo, /* default options (datagram) */
messlen, /* message length */
buffer, /* message buffer */
&CompCode, /* completion code */
&Reason); /* reason code */
What should i change so that i can send the structure
thanks and regards |
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| mvic |
| Posted: Tue May 16, 2006 1:53 am Post subject: |
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Jedi
Joined: 09 Mar 2004
Posts: 2080
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| keerthikumar wrote: |
| What should i change so that i can send the structure |
Don't use MQFMT_STRING; this indicates to MQ that your message contains character data encoded in the CCSID you store in md.CodedCharSetId
Here's a good place to start reading about sending/converting known-user-format messages : http://publib.boulder.ibm.com/infocenter/wmqv6/v6r0/topic/com.ibm.mq.csqzak.doc/convx.htm
(NB. If you are always sending between similar machines, you could plan not to use data conversion at all. This is a detail I didn't see in the problem description).
EDIT: tiny editorial change to paragraph 1
Last edited by mvic on Tue May 16, 2006 8:03 am; edited 1 time in total |
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| EddieA |
| Posted: Tue May 16, 2006 7:53 am Post subject: |
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Jedi
Joined: 28 Jun 2001
Posts: 2453
Location: Los Angeles
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Or, if you do need to convert the data between code pages, you could convert the non-character data to character for the "journey", and then convert back at the other end.
Cheers,
_________________
Eddie Atherton
IBM Certified Solution Developer - WebSphere Message Broker V6.1
IBM Certified Solution Developer - WebSphere Message Broker V7.0 |
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| jefflowrey |
| Posted: Tue May 16, 2006 9:18 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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you could convert the non-character data to character for the "journey", and then convert back at the other end.
Or instead of building a language and endian-specific message, you could do something more platform neutral like represent the data as XML, and write it to the message as a string.
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| RogerLacroix |
| Posted: Tue May 16, 2006 10:08 pm Post subject: |
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Jedi Knight
Joined: 15 May 2001
Posts: 3265
Location: London, ON Canada
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| keerthikumar wrote: |
struct sCustomerDetails
{
struct sPersonalDetails personaldetails;
struct sAccountDetails accountdetails;
}custdetails;
...
unsigned char buffer[500];
struct sCustomerDetails * temp;
temp=&custdetails;
memcpy(buffer,temp,sizeof(custdetails)); |
Hi,
This is a C programming error and has nothing to do with MQ. Any decent debugger would have shown the result of sizeof(custdetails) and you would known what the problem was (hopefully known).
| keerthikumar wrote: |
| but I could not copy entire structure only custdetails.sPersonalDetails.acCustID was only copied |
Impossible. That field has a length of 10. You are actually ONLY copying 8 bytes.
Dig out your C programming references and look up struct and struct within a struct. This will lead you to the answer.
Regards,
Roger Lacroix
Capitalware Inc.
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Capitalware: Transforming tomorrow into today.
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| tleichen |
| Posted: Wed May 17, 2006 11:13 am Post subject: |
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Yatiri
Joined: 11 Apr 2005
Posts: 663
Location: Center of the USA
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I suppose now we have to teach the inexperienced how to write code too? 
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| leehairy |
| Posted: Tue Aug 08, 2006 3:32 am Post subject: |
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Novice
Joined: 04 Aug 2006
Posts: 13
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I dont get the last comment..
RogerLacroix - What would make you think that structs in structs would not be the cumulative size of a structure?
The struct does not contain pointers to other structures. Did you misread?
sizeof(custDetails) is 232 == sizeof(struct sCustomerDetails)
which is correct..
| Quote: |
keerthikumar wrote:
but I could not copy entire structure only custdetails.sPersonalDetails.acCustID was only copied |
Do you mean only 10 bytes where copied to char *buffer or only 10 bytes appeared on the queue?
My little test harness based seems to work fine ...
| Code: |
// con1.cpp : Defines the entry point for the console application.
//
#include <string.h>
struct sAccountDetails
{
char acAccType[10];
double fbalance;
};
struct sPersonalDetails
{
char acCustID[10];
char acCustFirstName[20];
char acCustLastName[20];
char acCustDOB[15];
char acCustAddress[100];
char acCustCity[15];
char acCustPincode[10];
char acCustPhone[12];
};
struct sCustomerDetails
{
struct sPersonalDetails personaldetails;
struct sAccountDetails accountdetails;
}custdetails;
int _tmain(int argc, _TCHAR* argv[])
{
strcpy(custdetails.accountdetails.acAccType, "10");
custdetails.accountdetails.fbalance = 10.0f;
strcpy(custdetails.personaldetails.acCustAddress, "add1");
strcpy(custdetails.personaldetails.acCustFirstName, "first");
strcpy(custdetails.personaldetails.acCustLastName, "last");
strcpy(custdetails.personaldetails.acCustDOB, "13-15-03");
strcpy(custdetails.personaldetails.acCustID, "10");
strcpy(custdetails.personaldetails.acCustCity, "bighton");
strcpy(custdetails.personaldetails.acCustPincode, "4738");
strcpy(custdetails.personaldetails.acCustPhone, "911");
unsigned char buffer[500];
memcpy(buffer,(char *)(&custdetails),sizeof(custdetails));
int l = (int)sizeof(sCustomerDetails);
int x = (int)sizeof(custdetails);
// unpack ...
struct sCustomerDetails unpack = { 0x00 };
memcpy((char *)&unpack, buffer, sizeof(struct sCustomerDetails));
return 0;
} |
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