ECPG and NULL indicators

============================================================================
POSTGRESQL BUG REPORT
============================================================================

Your name : Edmund Bacon
Your email address : ebacon (at) onesystem (dot) com

System Configuration
---------------------
Architecture : Intel Pentium

Operating System : Linux 2.4.20

PostgreSQL version : PostgreSQL-7.3.3

Compiler used : gcc-3.2.2

Please enter a FULL description of your problem:
------------------------------------------------

ecpg does not correctly set null indicators when storage for the
string is dynamically allocated

Please describe a way to repeat the problem. Please try to provide a
concise reproducible example, if at all possible:
----------------------------------------------------------------------

CREATE TABLE strings (string text);

insert into strings values('able');
insert into strings values(null);
insert into strings values('baker');
insert into strings values(null);

Source for foo.pgc:

============================================================

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

EXEC SQL WHENEVER SQLERROR sqlprint;

EXEC SQL INCLUDE sqlca;

int main()
{
int i;
EXEC SQL BEGIN DECLARE SECTION;
char **a_str;
int *a_str_ind;

char str[5][20];
int str_ind[5];
EXEC SQL END DECLARE SECTION;

EXEC SQL CONNECT TO test;

printf("Test one: alloced string, allocated indicator:\n");

a_str = NULL;
a_str_ind = NULL;

EXEC SQL SELECT string INTO :a_str :a_str_ind FROM strings;

printf("indicator string\n");
for(i = 0; i < sqlca.sqlerrd[2]; i++)
printf("%8d \"%s\"\n", a_str_ind[i], a_str[i]);

free(a_str);
free(a_str_ind);

printf("\nTest two: alloced string, unalloced indicator:\n");
a_str = NULL;
for(i = 0; i < 5; i++) str_ind[i] = 99;

EXEC SQL SELECT string INTO :a_str :str_ind FROM strings;

printf("indicator string\n");
for(i = 0; i < sqlca.sqlerrd[2]; i++)
printf("%8d \"%s\"\n", str_ind[i], a_str[i]);

free(a_str);

printf("\nTest three: unalloced string, alloced indicator:\n");
a_str_ind = NULL;
bzero(str, sizeof(str));

EXEC SQL SELECT string INTO :str :a_str_ind FROM strings;
printf("indicator string\n");
for(i = 0; i < sqlca.sqlerrd[2]; i++)
printf("%8d \"%s\"\n", a_str_ind[i], str[i]);

free(a_str_ind);

printf("\nTest four: unalloced string, unalloced indicator:\n");
bzero(str, sizeof(str));
for(i = 0; i < 5; i++) str_ind[i] = 99;

EXEC SQL SELECT string INTO :str :str_ind FROM strings;
printf("indicator string\n");
for(i = 0; i < sqlca.sqlerrd[2]; i++)
printf("%8d \"%s\"\n", str_ind[i], str[i]);

return 0;
}

==================================================================

Output for foo:
==================================================================
Test one: alloced string, allocated indicator:
indicator string
-1 "able"
0 ""
0 "baker"
0 ""

Test two: alloced string, unalloced indicator:
indicator string
-1 "able"
99 ""
99 "baker"
99 ""

Test three: unalloced string, alloced indicator:
indicator string
0 "able"
-1 ""
0 "baker"
-1 ""

Test four: unalloced string, unalloced indicator:
indicator string
0 "able"
-1 ""
0 "baker"
-1 ""

==================================================================

Note that when the storage for the string is allocated, only the first
element of the indicator array is set. This value is the value of
the indicator for the last string in the string array, which can be
confirmed by using the appropriate ORDER BY clause.

This problem does not arise with allocated integer or float values.
This problem occurs if string is any multi-char type (e.g. TEXT, CHAR(),
or VARCHAR())

I can confirm this ecpg bug exists in current CVS. Let me see if the
ecpg guy can look at it soon.

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

Edmund Bacon wrote:
>
> ============================================================================
> POSTGRESQL BUG REPORT
> ============================================================================
>
>
> Your name : Edmund Bacon
> Your email address : ebacon (at) onesystem (dot) com
>
>
> System Configuration
> ---------------------
> Architecture : Intel Pentium
>
> Operating System : Linux 2.4.20
>
> PostgreSQL version : PostgreSQL-7.3.3
>
> Compiler used : gcc-3.2.2
>
>
> Please enter a FULL description of your problem:
> ------------------------------------------------
>
> ecpg does not correctly set null indicators when storage for the
> string is dynamically allocated
>
>
> Please describe a way to repeat the problem. Please try to provide a
> concise reproducible example, if at all possible:
> ----------------------------------------------------------------------
>
> CREATE TABLE strings (string text);
>
> insert into strings values('able');
> insert into strings values(null);
> insert into strings values('baker');
> insert into strings values(null);
>
>
> Source for foo.pgc:
>
> ============================================================
>
> #include <stdio.h>
> #include <stdlib.h>
> #include <string.h>
>
> EXEC SQL WHENEVER SQLERROR sqlprint;
>
> EXEC SQL INCLUDE sqlca;
>
> int main()
> {
> int i;
> EXEC SQL BEGIN DECLARE SECTION;
> char **a_str;
> int *a_str_ind;
>
> char str[5][20];
> int str_ind[5];
> EXEC SQL END DECLARE SECTION;
>
>
> EXEC SQL CONNECT TO test;
>
>
> printf("Test one: alloced string, allocated indicator:\n");
>
> a_str = NULL;
> a_str_ind = NULL;
>
> EXEC SQL SELECT string INTO :a_str :a_str_ind FROM strings;
>
> printf("indicator string\n");
> for(i = 0; i < sqlca.sqlerrd[2]; i++)
> printf("%8d \"%s\"\n", a_str_ind[i], a_str[i]);
>
> free(a_str);
> free(a_str_ind);
>
>
> printf("\nTest two: alloced string, unalloced indicator:\n");
> a_str = NULL;
> for(i = 0; i < 5; i++) str_ind[i] = 99;
>
> EXEC SQL SELECT string INTO :a_str :str_ind FROM strings;
>
> printf("indicator string\n");
> for(i = 0; i < sqlca.sqlerrd[2]; i++)
> printf("%8d \"%s\"\n", str_ind[i], a_str[i]);
>
> free(a_str);
>
>
> printf("\nTest three: unalloced string, alloced indicator:\n");
> a_str_ind = NULL;
> bzero(str, sizeof(str));
>
> EXEC SQL SELECT string INTO :str :a_str_ind FROM strings;
> printf("indicator string\n");
> for(i = 0; i < sqlca.sqlerrd[2]; i++)
> printf("%8d \"%s\"\n", a_str_ind[i], str[i]);
>
> free(a_str_ind);
>
>
> printf("\nTest four: unalloced string, unalloced indicator:\n");
> bzero(str, sizeof(str));
> for(i = 0; i < 5; i++) str_ind[i] = 99;
>
> EXEC SQL SELECT string INTO :str :str_ind FROM strings;
> printf("indicator string\n");
> for(i = 0; i < sqlca.sqlerrd[2]; i++)
> printf("%8d \"%s\"\n", str_ind[i], str[i]);
>
>
> return 0;
> }
>
> ==================================================================
>
> Output for foo:
> ==================================================================
> Test one: alloced string, allocated indicator:
> indicator string
> -1 "able"
> 0 ""
> 0 "baker"
> 0 ""
>
> Test two: alloced string, unalloced indicator:
> indicator string
> -1 "able"
> 99 ""
> 99 "baker"
> 99 ""
>
> Test three: unalloced string, alloced indicator:
> indicator string
> 0 "able"
> -1 ""
> 0 "baker"
> -1 ""
>
> Test four: unalloced string, unalloced indicator:
> indicator string
> 0 "able"
> -1 ""
> 0 "baker"
> -1 ""
>
> ==================================================================
>
> Note that when the storage for the string is allocated, only the first
> element of the indicator array is set. This value is the value of
> the indicator for the last string in the string array, which can be
> confirmed by using the appropriate ORDER BY clause.
>
> This problem does not arise with allocated integer or float values.
> This problem occurs if string is any multi-char type (e.g. TEXT, CHAR(),
> or VARCHAR())
>
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 2: you can get off all lists at once with the unregister command
> (send "unregister YourEmailAddressHere" to majordomo(at)postgresql(dot)org)
>

--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073

On Sun, Oct 26, 2003 at 01:19:57AM -0400, Bruce Momjian wrote:
>
> I can confirm this ecpg bug exists in current CVS. Let me see if the
> ecpg guy can look at it soon.

Fix just committed to CVS. Thanks for the report.

Michael
--
Michael Meskes
Email: Michael at Fam-Meskes dot De
ICQ: 179140304, AIM/Yahoo: michaelmeskes, Jabber: meskes(at)jabber(dot)org
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