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

#define RESULT_LEN  256

#define CHECK_ERROR(e, s, h, t) ({\
            if (e!=SQL_SUCCESS && e != SQL_SUCCESS_WITH_INFO) {extract_error(s, h, t); goto exit;} \
})
void extract_error(char *fn, SQLHANDLE handle, SQLSMALLINT type)
{
    SQLINTEGER i = 0;
    SQLINTEGER NativeError;
    SQLCHAR SQLState[ 7 ];
    SQLCHAR MessageText[256];
    SQLSMALLINT TextLength;
    SQLRETURN ret;

    fprintf(stderr, "\nThe driver reported the following error %s\n", fn);
    do
    {
        ret = SQLGetDiagRec(type, handle, ++i, SQLState, &NativeError,
                            MessageText, sizeof(MessageText), &TextLength);
        if (SQL_SUCCEEDED(ret)) {
            printf("%s:%ld:%ld:%s\n",
                        SQLState, (long) i, (long) NativeError, MessageText);
        }
    }
    while( ret == SQL_SUCCESS );
}
int main () {

    SQLHENV   henv  = SQL_NULL_HENV;   // Environment
    SQLHDBC   hdbc  = SQL_NULL_HDBC;   // Connection handle
    SQLHSTMT  hstmt = SQL_NULL_HSTMT;  // Statement handle
    SQLRETURN retcode;
    SQLCHAR strResult[RESULT_LEN];
    SQLCHAR outstr[1024];
    SQLSMALLINT outstrlen;
    int i=0;
    // Allocate environment handle
    retcode = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &henv);
    CHECK_ERROR(retcode, "SQLAllocHandle(SQL_HANDLE_ENV)",
                henv, SQL_HANDLE_ENV);
    // Set the ODBC version environment attribute
    retcode = SQLSetEnvAttr(henv, SQL_ATTR_ODBC_VERSION,
                            (SQLPOINTER*)SQL_OV_ODBC3, 0);
    CHECK_ERROR(retcode, "SQLSetEnvAttr(SQL_ATTR_ODBC_VERSION)",
                henv, SQL_HANDLE_ENV);
    // Allocate connection handle
    retcode = SQLAllocHandle(SQL_HANDLE_DBC, henv, &hdbc);
    CHECK_ERROR(retcode, "SQLAllocHandle(SQL_HANDLE_DBC)",
                hdbc, SQL_HANDLE_DBC);
    // Set login timeout to 5 seconds
    SQLSetConnectAttr(hdbc, SQL_LOGIN_TIMEOUT, (SQLPOINTER)5, 0);
    CHECK_ERROR(retcode, "SQLSetConnectAttr(SQL_LOGIN_TIMEOUT)",
                hdbc, SQL_HANDLE_DBC);
    // Connect to data source
    retcode = SQLDriverConnect(hdbc, NULL, "Driver=ODBC Driver 13 for SQL Server;Server=<yourserver>;Uid=<yourusername>;Pwd=<yourpassword>;database=<yourdatabase>", SQL_NTS, outstr, sizeof(outstr), &outstrlen, SQL_DRIVER_NOPROMPT);
    // Allocate statement handle
    retcode = SQLAllocHandle(SQL_HANDLE_STMT, hdbc, &hstmt);
    CHECK_ERROR(retcode, "SQLAllocHandle(SQL_HANDLE_STMT)",
                hstmt, SQL_HANDLE_STMT);
    retcode = SQLExecDirect(hstmt,
                            (SQLCHAR*) "SELECT @@Version", SQL_NTS);
    CHECK_ERROR(retcode, "SQLExecDirect()", hstmt, SQL_HANDLE_STMT);

    // Bind columns

    retcode = SQLBindCol(hstmt, 1, SQL_C_CHAR, &strResult, RESULT_LEN, 0);


    // Fetch and print each row of data until SQL_NO_DATA returned.
    for (i=0; ; i++) {
        retcode = SQLFetch(hstmt);
        if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {
               printf("Result is: %s", strResult);
        } else {
            if (retcode != SQL_NO_DATA) {
                CHECK_ERROR(retcode, "SQLFetch()", hstmt, SQL_HANDLE_STMT);
            } else {
                break;
            }
        }
    }

exit:

    printf ("\nComplete.\n");
    // Free handles
    // Statement
    if (hstmt != SQL_NULL_HSTMT)
        SQLFreeHandle(SQL_HANDLE_STMT, hstmt);
    // Connection
    if (hdbc != SQL_NULL_HDBC) {
        SQLDisconnect(hdbc);
        SQLFreeHandle(SQL_HANDLE_DBC, hdbc);
    }
    // Environment
    if (henv != SQL_NULL_HENV)
        SQLFreeHandle(SQL_HANDLE_ENV, henv);
    return 0;
}