How to access MS SQL server by ODBC with C/C++ on linux

For ODBC setting on linux, please refer to my https://steemit.com/cn/@alanzheng/php-steemsql

The demo C code is here, for example file name is queryInfo.c:

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

void main( int argc, char** argv ) {
SQLHENV env;
SQLHDBC dbc;
SQLHSTMT stmt;
SQLRETURN ret; /* ODBC API return status */
SQLSMALLINT columns; /* number of columns in result-set */
int row = 0;
char sql[1024] = "";

/* Allocate an environment handle */
SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &env);
/* We want ODBC 3 support */
SQLSetEnvAttr(env, SQL_ATTR_ODBC_VERSION, (void *) SQL_OV_ODBC3, 0);
/* Allocate a connection handle */
SQLAllocHandle(SQL_HANDLE_DBC, env, &dbc);
/* Connect to the DSN mydsn */
/* You will need to change mydsn to one you have created and tested */
SQLDriverConnect(dbc, NULL, "DSN=steemDB;Uid=steemit;Pwd=steemit", SQL_NTS,
                 NULL, 0, NULL, SQL_DRIVER_COMPLETE);
/* Allocate a statement handle */
SQLAllocHandle(SQL_HANDLE_STMT, dbc, &stmt);
/* execute a query */
if( argc > 1 )
sprintf(sql, "select voting_power from Accounts where name='%s'", argv[1]);
else
{
    printf("No username given\n");
    return;
}
SQLExecDirect(stmt, sql, SQL_NTS);
/* How many columns are there */
SQLNumResultCols(stmt, &columns);
/* Loop through the rows in the result-set */
while (SQL_SUCCEEDED(ret = SQLFetch(stmt))) {
    SQLUSMALLINT i;
    printf("Row %d\n", row++);
    /* Loop through the columns */
    for (i = 1; i <= columns; i++) {
        SQLINTEGER indicator;
        char buf[512];
        /* retrieve column data as a string */
        ret = SQLGetData(stmt, i, SQL_C_CHAR,
                         buf, sizeof(buf), &indicator);
        if (SQL_SUCCEEDED(ret)) {
            /* Handle null columns */
            if (indicator == SQL_NULL_DATA) sprintf(buf, "%s", "NULL");
            printf("  Column %u : %s\n", i, buf);
        }
    }
  }
}

Then gcc compile it: gcc queryInfo.c -o queryInfo -lodbc

To run it: ./queryInfo alanzheng
Now I got my voting_power is 9077