Re: C coding

I've done some very serious programming with C/400. It's a message oriented middleware (much like MQ) with all important parts in C (some RPG for UI). It's a fully autonomous system, extremely performant and stable. It has handled approx 1 billion transactions the last 20 years...
So yes, it can be done. Style= Pseudo object oriented.

/Joakim


> 10 feb 2014 kl. 22:59 skrev "frank kolmann" <[email protected]>:
>
> Hi
>
> Having done a first pass on learning C using the K&R  The C programming
> Language I am
>
> Now doing the examples in ILE C for AS/400(R) Programmer's Guide.
> The below is an example of a program in the IBM Guide.
> The IBM code seems to me to be a trivial example of what C is capable of.
> Scott you mentioned before when I posted a question on C Syntax Errors that
> the
>
> Code  posted was 'Absolutely horrible code'.  At the time your comment did
> not really
> register with me.  I well respect your opinion and I have learnt a lot from
> you.
> I would be grateful to hear your views on how to write C code.
>
>> From my reviews  of what is said on the net about C code,
>
> I have stumbled on these points.
>
> Professional C programmers use a subset of C that they have found
>
> best suits their needs.
>
> It is easy to introduce errors in C codes that lead to the infamous
> 'memory leaks' and such errors can be very hard to find.
> So hard in fact that some C projects have failed.
>
> Debugging C can be hard because a single line can be a looping function and
>
> the error can be inside the loop but the debugger cannot see that level of
>
> detail unless you debug intermediate source  and the intermediate source
>
> can be so arcane you still cannot find the error.
>
> So I am prompted to ask, is anyone doing serious coding in C on the AS400.
> And if so what is the application and more interesting to me what style of
> C code is being used?
>
>
>
> Regards
> Frank Kolmann
>
>
>
> http://publib.boulder.ibm.com/infocenter/iadthelp/v7r0/index.jsp?topic=/com.ibm.etools.iseries.pgmgd.doc/cpprog162.htm
>
>
>
>          /* This function writes an audit trail. To write the audit trail
> the  */
>
>          /* file field structure is retrieved from the DDS file T1520DD1
> and   */
>
>          /* the taxrate data item is imported from service program
> T1520SP2.   */
>
>          /* Retrieves the file field structure.
>          */
>
>          #pragma mapinc("myinc", "MYLIB/T1520DD1(*all)", "both", "p z","")
>
>          #include <stdio.h>
>
>          #include <stdlib.h>
>
>          #include <string.h>
>
>          #include <time.h>
>
>          #include <decimal.h>
>
>          #include <recio.h>
>
>          #include <xxcvt.h>
>
>          /* These includes are for the call to QWCCVTDT API to get the
> system  */(1)
>
>          /* date to be used in the audit
> trail.                                */
>
>          #include <QSYSINC/H/QWCCVTDT>
>
>          #include <QSYSINC/H/QUSEC>
>
>          /* DDS mapping of the audit file,
> T1520DD1.                           */(2)
>
>          #include "myinc"
>
>          /* Tax rate is imported from service program
> T1520SP2.                */(3)
>
>          const extern decimal (2,2) taxrate;
>
>          void write_audit_trail (char             user_id[10],
>
>                                  char             item_name[],
>
>                                  decimal (10,2)   price,
>
>                                  short int        quantity,
>
>                                  char             formatted_cost[22])
>
>          {
>
>              char  char_item_name[21];
>
>              char  char_price[11];
>
>              char  temp_char_price[11];
>
>              char  char_quantity[4];
>
>              char  char_date[6];
>
>              char  char_taxrate[2];
>
>           /* Qus_EC_t is defined in
> QUSEC.                                      */
>
>              Qus_EC_t errcode;
>
>              char    get_date[16];
>
>              int     i;
>
>              double  d;
>
>           /* File field structure is generated by the #pragma mapinc
> directive. */
>
>              MYLIB_T1520DD1_T1520DD1R_both_t buf1;
>
>              _RFILE *fp;
>
>           /* Get the current date.
>                                     */
>
>              errcode.Bytes_Provided = 0;
>
>              QWCCVTDT ("*CURRENT  ", "", "*MDY      ", get_date, &errcode);
>
>              memcpy (char_date, &(get_date[1]), 6);
>
>           /* Loop through the item_name and remove the null
> terminator.         */
>
>              for (i=0; i<=20; i++)
>
>              {
>
>                if (item_name[i] == '\0') char_item_name[i] = ' ';
>
>                else char_item_name[i] = item_name[i];
>
>              }
>
>           /* Convert packed to zoned for audit
> file.                            */
>
>              d = price;
>
>              QXXDTOZ (char_price, 10, 2, d);
>
>              QXXITOZ (char_quantity, 4, 0, quantity);
>
>              d = taxrate;
>
>              QXXDTOZ (char_taxrate, 2, 2, d);
>
>           /* Set up buffer for
> write.                                           */
>
>              memset(&buf1, ' ',  sizeof(buf1));
>
>              memcpy(buf1.USER,   user_id, 10);
>
>              memcpy(buf1.ITEM,   char_item_name, 20);
>
>              memcpy(buf1.PRICE,  char_price, 11);
>
>              memcpy(buf1.QTY,    char_quantity, 4);
>
>              memcpy(buf1.TXRATE, char_taxrate, 2);
>
>              memcpy(buf1.TOTAL,  formatted_cost, 21);
>
>              memcpy(buf1.DATE,   char_date, 6);
>
>              if ((fp = _Ropen("MYLIB/T1520DD1", "ar+")) == NULL)
>
>              {
>
>                printf("Cannot open audit file\n");
>
>              }
>
>                _Rwrite(fp, (void *)&buf1, sizeof(buf1));
>
>                _Rclose(fp);
>              }
>> date: Fri, 17 Jan 2014 20:13:16 -0600
>> from: Scott Klement <[email protected]>
>> subject: Re: [C400-L] C syntax errors
>>
>> Not to mention that it uses global variables (and even extern variables)
>> throughout instead of parameters...
>>
>> Absolutely horrible code.  Definitely not to be used as an example!.
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