Getting segmentation fault while outputting the result of the MySQL query - mysql

Question

I have a simple program that should print today's day name. It was working, but I made the get_query_result function and after that, it is giving me a segmentation fault.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <mysql.h>
#define QUERY_SIZE 1000
void finish_with_error(MYSQL* con)
{
fprintf(stderr, "%s\n", mysql_error(con));
mysql_close(con);
exit(1);
}
void get_query_result(MYSQL *con, MYSQL_RES *result, char *query)
{
if(mysql_query(con, query))
{
finish_with_error(con);
}
result = mysql_store_result(con);
if(result == NULL)
{
finish_with_error(con);
}
}
int main()
{
MYSQL *con = mysql_init(NULL);
MYSQL_RES *result;
MYSQL_ROW row;
if(con == NULL)
{
fprintf(stderr, "mysql_init() failed\n");
exit(1);
}
if(mysql_real_connect(con, "127.0.0.1", "root", "mysqlpassword", "database", 0, NULL, 0) == NULL)
{
finish_with_error(con);
}
get_query_result(con, result, "SELECT DAYNAME(DATE(NOW()))");
row = mysql_fetch_row(result);
printf("%s\n", row[0]);
mysql_free_result(result);
return 0;
}

Answer 1

result in main is not affected by get_query_result, in consequence, you end up calling mysql_free_result with an uninitialized pointer.
Switch to
MYSQL_RES *get_query_result(MYSQL *con, char *query)
{
MYSQL_RES *result;
if(mysql_query(con, query))
{
finish_with_error(con);
}
result = mysql_store_result(con);
if(result == NULL)
{
finish_with_error(con);
}
return result;
}
and call it like:
result = get_query_result(con, "SELECT DAYNAME(DATE(NOW()))");