//First, precompile it by
//  $ORACLE_HOME/bin/proc iname=oracle.pc code=cpp parse=none
//
//Then, compile it by
//  g++ -I$ORACLE_HOME/precomp/public/ oracle.c -L$ORACLE_HOME/lib/ -lclntsh -laio -lm
//
//At last, run it by
//  ./a.out

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

void sql_error(char *msg)
{
  printf("%s", msg);
  exit(1);
}

int main()
{
  char temp_char[32];

  //declear host variables
  EXEC SQL BEGIN DECLARE SECTION;
  VARCHAR username[32];
  VARCHAR password[32];
  VARCHAR str[33];
  EXEC SQL END DECLARE SECTION;

  //Copy the username and password into the VARCHAR.
  strncpy((char *) username.arr, "YOUR_USERNAME", 32);
  username.len = strlen((char *) username.arr);
  strncpy((char *) password.arr, "YOUR_PASSWORD", 32);
  password.len = strlen((char *) password.arr);

  //Register sql_error() as the error handler.
  EXEC SQL WHENEVER SQLERROR DO sql_error("ORACLE ERROR: \n");

  //Connect to ORACLE.  Program will call sql_error()
  //if an error occurs when connecting to the default database.
  EXEC SQL CONNECT :username IDENTIFIED BY :password;
  printf("\nConnected to ORACLE as user: %s\n", username.arr);

  //create a table
  EXEC SQL CREATE TABLE hello (message varchar(32));

  //insert data
  EXEC SQL INSERT INTO hello VALUES ('Hello World!');

  //query the db
  EXEC SQL DECLARE tmp CURSOR FOR SELECT message FROM hello;
  EXEC SQL OPEN tmp;
  EXEC SQL WHENEVER NOT FOUND DO break;
  for (;;)
  {
    EXEC SQL FETCH tmp INTO :str;
    str.arr[str.len] = '\0';
    printf("%s\n", str.arr);
  }
  EXEC SQL CLOSE tmp;

  // Disconnect from ORACLE
  EXEC SQL COMMIT WORK RELEASE;
  exit(0);
}