/** 
 * Sourced from Microsoft sqlblog:
 * http://blogs.msdn.com/b/sqlblog/archive/2012/01/26/use-existing-msdn-c-odbc-samples-for-microsoft-linux-odbc-driver.aspx
 *
 * Original title:
 *  Use Existing MSDN C++ ODBC Samples for Microsoft Linux ODBC Driver
 *  By Gregory Suarez | Sr. Escalation Engineer | SQL Server
 *
 *
 * Slightly adapted:
 *  - loop initial declarations are only allowed in C99 mode
 *
 * Compile and link this program using:
 *   gcc sqlncli-msdn-odbc-example.c -o sqlncli-msdn-odbc-example -lodbc
 *
**/
#include <stdio.h>
#include <stdlib.h>
#include <sqlext.h>
#include <sql.h>

#define NAME_LEN 50
#define PHONE_LEN 20

void show_error() {
   printf("error\n");
}

int main() {
   SQLHENV henv;
   SQLHDBC hdbc;
   SQLHSTMT hstmt = 0;
   SQLRETURN retcode;
   SQLCHAR szName[NAME_LEN], szPhone[PHONE_LEN], sCustID[NAME_LEN];
   SQLLEN cbName = 0, cbCustID = 0, cbPhone = 0;

   // Allocate environment handle
   retcode = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &henv);

   // Set the ODBC version environment attribute
   if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {
      retcode = SQLSetEnvAttr(henv, SQL_ATTR_ODBC_VERSION, (SQLPOINTER*)SQL_OV_ODBC3, 0);

      // Allocate connection handle
      if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {
         retcode = SQLAllocHandle(SQL_HANDLE_DBC, henv, &hdbc);

         // Set login timeout to 5 seconds
         if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {
            SQLSetConnectAttr(hdbc, SQL_LOGIN_TIMEOUT, (SQLPOINTER)5, 0);

            // Connect to data source
            retcode = SQLConnect(hdbc, (SQLCHAR*) "SQLCMD", SQL_NTS, (SQLCHAR*) "Test1", 5, (SQLCHAR*) "Password1", 9);

            // Allocate statement handle
            if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {
               retcode = SQLAllocHandle(SQL_HANDLE_STMT, hdbc, &hstmt);

               retcode = SQLExecDirect (hstmt, (SQLCHAR *) "SELECT CustomerID, ContactName, Phone FROM CUSTOMERS ORDER BY 2, 1, 3", SQL_NTS);
               if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {

                  // Bind columns 1, 2, and 3
                  retcode = SQLBindCol(hstmt, 1, SQL_C_CHAR, sCustID, 100, &cbCustID);
                  retcode = SQLBindCol(hstmt, 2, SQL_C_CHAR, szName, NAME_LEN, &cbName);
                  retcode = SQLBindCol(hstmt, 3, SQL_C_CHAR, szPhone, PHONE_LEN, &cbPhone);

                  // Fetch and print each row of data. On an error, display a message and exit.
		  int i;
                  for (i=0 ; ; i++) {
                     retcode = SQLFetch(hstmt);
                     if (retcode == SQL_ERROR || retcode == SQL_SUCCESS_WITH_INFO)
                        show_error();
                     if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO)
                        printf( "%d: %s %s %s\n", i + 1, sCustID, szName, szPhone);
                     else
                        break;
                  }
               }

               // Process data
               if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {
                  SQLCancel(hstmt);
                  SQLFreeHandle(SQL_HANDLE_STMT, hstmt);
               }

               SQLDisconnect(hdbc);
            }

            SQLFreeHandle(SQL_HANDLE_DBC, hdbc);
         }
      }
      SQLFreeHandle(SQL_HANDLE_ENV, henv);
   }
}