Conference turris::decc

2144.0. "char *String = char *String[] ?" by GIDDAY::SHCHIU () Wed Apr 09 1997 01:15

                                                          


I have a customer site reports problem with following C program, Written
under VAXC V3.2. works and C is now upg to v5.5 on VAX/VMS , and also
on ALPHA/VMS installed DECC v5.5.


the code is generated run time error.

to make it works , "[]" is inserted after  char Mystring.

Question : 

1. Has strtok() been change since vaxc v3.2 ?
   Is char Mystring = is valid expression  for this case ??



rgds

/stanley 



 ty doeswork.c
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
main ()
{
/******************* Code that does work with the addition of [ ]. */
   char Mystring[]="This is the ,1-Jan-1997 00:01:00,67,123,1.1,1.2";
   char *StartString;
   int Index;
   printf ("%s, Length=%d \n", Mystring,strlen(Mystring));
   StartString= strtok(Mystring,",");
   Index=0;
   while (StartString != NULL)
   {
      Index++;
      printf ("%s Length=%d \n", StartString,strlen(StartString));
      if (Index >=3)
      {
         printf(" Index is %d \n",Index);
         printf(" Conversion is %d \n",atol(StartString));
      };
         StartString= strtok(NULL,",");
   };
}

$

----------------------

$ ty doesnotwork.c
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
main ()
{
/******************* Code that doesn't work is the following line. */
   char *Mystring="This is the ,1-Jan-1997 00:01:00,67,123,1.1,1.2";
   char *StartString;
   int Index;
   printf ("%s, Length=%d \n", Mystring,strlen(Mystring));
   StartString= strtok(Mystring,",");
   Index=0;
   while (StartString != NULL)
   {
      Index++;
      printf ("%s Length=%d \n", StartString,strlen(StartString));
      if (Index >=3)
      {
         printf(" Index is %d \n",Index);
         printf(" Conversion is %d \n",atol(StartString));
      };
         StartString= strtok(NULL,",");
   };
}

$

$ cc/ver/noobj nl:
DEC C V5.3-006 on OpenVMS Alpha V6.2
$

$ run doesnotwork
This is the ,1-Jan-1997 00:01:00,67,123,1.1,1.2, Length=47
%SYSTEM-F-ACCVIO, access violation, reason mask=04, virtual address=00010124, PC
=805ADEAC, PS=0000001B
%TRACE-F-TRACEBACK, symbolic stack dump follows
 Image Name   Module Name     Routine Name    Line Number  rel PC      abs PC
                                                        0 805ADEAC    805ADEAC
 DOESNOTWORK  DOESNOTWORK     main                   1965 00000114    00020114
 DOESNOTWORK  DOESNOTWORK     __main                    0 00000064    00020064
                                                        0 832D4170    832D4170
$


$ run doeswork
This is the ,1-Jan-1997 00:01:00,67,123,1.1,1.2, Length=47
This is the  Length=12
1-Jan-1997 00:01:00 Length=19
67 Length=2
 Index is 3
 Conversion is 67
123 Length=3
 Index is 4
 Conversion is 123
1.1 Length=3
 Index is 5
 Conversion is 1
1.2 Length=3
 Index is 6
 Conversion is 1
$




---------------------------


Ripper_> cc/noobj/ver nl:
DEC C V5.2-003 on OpenVMS VAX V6.1
Ripper_>

Ripper_> run doesnotwork
This is the ,1-Jan-1997 00:01:00,67,123,1.1,1.2, Length=47
%SYSTEM-F-ACCVIO, access violation, reason mask=04, virtual address=0000020C, PC
=000836F4, PSL=03C00000
%TRACE-F-TRACEBACK, symbolic stack dump follows
module name     routine name                     line       rel PC    abs PC

                                                           000836F4  000836F4
DOESNOTWORK     main                             1963      00000041  000002B9
Ripper_>
ipper_> run doeswork
This is the ,1-Jan-1997 00:01:00,67,123,1.1,1.2, Length=47
This is the  Length=12
1-Jan-1997 00:01:00 Length=19
67 Length=2
 Index is 3
 Conversion is 67
123 Length=3
 Index is 4
 Conversion is 123
1.1 Length=3
 Index is 5
 Conversion is 1
1.2 Length=3
 Index is 6
 Conversion is 1
Ripper_>

    

>   char Mystring[]="This is the ,1-Jan-1997 00:01:00,67,123,1.1,1.2";
This creates a 48-byte variable, initialized to the value shown here.

>   char *Mystring="This is the ,1-Jan-1997 00:01:00,67,123,1.1,1.2";
This creates a pointer to a 48-byte constant.

>   StartString= strtok(Mystring,",");
This tries to replace the first "," with a null.

In the case that works, you're storing into a variable -- no problem.
In the case that doesn't work, you're trying to store into a constant,
and DEC C doesn't allow that by default.  VAX C did allow it, and you
can get DEC C to allow it by using a compile qualifier
/ASSUME=WRITABLE_STRING_LITERALS.  (Compiling with /STANDARD=VAXC turns
on this switch for you.)