Bug #12172 segmentation fault in c code using mysql API

• Submitted: 26 Jul 2005 9:18
• Modified: 2 Aug 2005 11:10
• Reporter: Emad Damra
• Status: Can't repeat
• Category: MySQL Server
• Severity: S2 (Serious)
• Version: mysql-5.0.3 beta statndard verion
• OS: Linux (Linux Redhat 9)
• CPU Architecture: Any

[26 Jul 2005 9:18] Emad Damra

Description:
i have my code in c using the MySql API library, but it give me a segmentation fault and it cause my other functions to exit on failed, so i use the following code, just to check if it in the mysql API functions or not , and give me in the end the same result "segmentation fault"
here is simply the code: <test.c>
#include <stdio.h>
#include "mysql.h"

MYSQL mysql;
MYSQL_RES *res;
MYSQL_ROW row;

int main()
{
             char q[512];
	
             bzero(q,sizeof(q));
             sprintf(q,"%s","select * from user_info;");
		
	mysql_init(&mysql);
	mysql_real_connect(&mysql,"localhost",NULL,NULL,NULL,0,NULL,0);
	mysql_select_db(&mysql,"MyDB");
	mysql_query(&mysql,q);	
	res=mysql_store_result(&mysql);
	while ((row = mysql_fetch_row(res))) 
	{
		printf("row=%s\n",row[0]);		
	}
	mysql_free_result(res);
	mysql_close(&mysql);
return 0;
}

and i compile the code by the following links:
gcc -o mytest mytest.c -I/usr/include/mysql -L/usr/lib/mysql -I. -lmysqlclient  -lz -lm

the output was like:{
row=admin
row=omdeh
row=emad
row=hmsom
Segmentation fault
}
it's amzing that the output return successfully from the database but i still have Segmentation fault, which cause another functions to failled!!!!!!!!!!!!!!

How to repeat:
i don't understatnd this field, relly, how to repeat the bug,
but my mail is [e-mail]

[26 Jul 2005 9:24] Jan Lindström

Could you please provide output  from show create table user_info and contents of that table
if there are not very many rows (e.g. doing select * from user_info in mysql client).

Regards,
   JanL

[26 Jul 2005 9:26] Emad Damra

hi
here is the output of your request:
+-----------+-----------------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------------------------------
------------------------------+
| Table     | Create Table                                                                                                          
                                                                                                                                    
                              |
+-----------+-----------------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------------------------------
------------------------------+
| user_info | CREATE TABLE `user_info` (
  `username` varchar(20) NOT NULL default '',
  `password` varchar(20) NOT NULL default '',
  `PrivilegeId` int(2) NOT NULL default '0',
  `GroupName` varchar(30) default NULL,
  UNIQUE KEY `username` (`username`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 |
+-----------+-----------------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------------------------------
------------------------------+
1 row in set (0.00 sec)

Thanks alot..:)

[2 Aug 2005 11:10] Andrey Hristov

Can't reproduce with 4.1.12 and 5.0.11-beta. As a side note C API does not check for consistency of the pointers passed to the library functions and every result from the API has be inspected in "user land".