FreeTDS Development Group

[Craig Davison <cd AT securityfocus.com>]

Sorry to reply to myself 3 times :)

Here's a sample program that illustrates the problem. To try, create a 
sp_return_nothing stored proc that returns no rowset, or create the one 
defined in the comments. You'll also need to change the DSN, user and 
password in main().

-- 
Craig Davison
Symantec Corporation
+1 (403) 213-3939 ext. 228
/* Create the stored proc as follows:
 *
 * CREATE PROCEDURE dbo.sp_return_nothing
 * AS BEGIN
 *      SELECT TOP 1 uid INTO #nothing FROM master..sysusers
 * END
 * GO
 */



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

int CheckSQLHandle (SQLSMALLINT SQLHandleType, SQLHSTMT hStmt, long erg, 
const char *pDesc)
{
  SQLINTEGER SQLerr;
  SQLSMALLINT SQLmsglen;
  char pStatus[10], pMsg[501];
  long erg2;

  if (erg != SQL_SUCCESS)
    {
      fprintf(stderr, "Error %s %ld\n", pDesc, erg);
      erg2 = SQLGetDiagRec(SQLHandleType, hStmt,1,
                           pStatus,&SQLerr,pMsg,500,&SQLmsglen);
      if (erg2 == SQL_SUCCESS)
        {
          fprintf(stderr, "%s (%d)\n",pMsg,(int)SQLerr);
        }
      else if (erg2 == SQL_SUCCESS_WITH_INFO)
        {
          fprintf(stderr, "Error buffer not large enough!\n");
        }
      return -1;
    }
  return 0;
}

void TryQuery (SQLHDBC hOdbc)
{
        SQLINTEGER SQLid;
        SQLINTEGER SQLerr;
        long erg;
        SQLHSTMT hStmt;
        char pQuery[501];

        SQLAllocHandle(SQL_HANDLE_STMT, hOdbc, &hStmt);
        sprintf (pQuery, "sp_return_nothing");
        printf ("First query: %s\n", pQuery);
        erg = SQLExecDirect (hStmt, pQuery, SQL_NTS);
        if (CheckSQLHandle (SQL_HANDLE_STMT, hStmt, erg, "First query"))
        {
                SQLFreeHandle(SQL_HANDLE_STMT, &hStmt);
                return;
        }
        SQLFreeStmt (hStmt, SQL_CLOSE);
        SQLFreeHandle(SQL_HANDLE_STMT, &hStmt);

        SQLAllocHandle(SQL_HANDLE_STMT, hOdbc, &hStmt);
        sprintf (pQuery, "SELECT uid FROM master..sysusers");
        printf ("Second query: %s\n", pQuery);
        SQLBindCol(hStmt, 1, SQL_C_SLONG, &SQLid, sizeof(SQLINTEGER), 
&SQLerr);
        erg = SQLExecDirect (hStmt, pQuery, SQL_NTS);
        if (CheckSQLHandle (SQL_HANDLE_STMT, hStmt, erg, "Second query"))
        {
                SQLFreeHandle(SQL_HANDLE_STMT, &hStmt);
                return;
        }
        erg = SQLFetch (hStmt);
        while (erg != SQL_NO_DATA && erg != SQL_ERROR)
        {
                printf ("Data: %d\n", (int)SQLid);
        }
        if (erg == SQL_ERROR && CheckSQLHandle (SQL_HANDLE_STMT, hStmt, erg,
                                "SQLFetch Second query"))
        {
                SQLFreeStmt (hStmt, SQL_CLOSE);
                SQLFreeHandle(SQL_HANDLE_STMT, &hStmt);
                return;
        }
        SQLFreeStmt (hStmt, SQL_CLOSE);
        SQLFreeHandle(SQL_HANDLE_STMT, &hStmt);
}

int main (int argc, char **argv)
{
        SQLHENV hEnv;
        SQLHDBC hOdbc;
        long erg;

        SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &hEnv);
        SQLSetEnvAttr(hEnv, SQL_ATTR_ODBC_VERSION, (void*)SQL_OV_ODBC3, 0);
        SQLAllocHandle(SQL_HANDLE_DBC, hEnv, &hOdbc);

        /* connect to the database */
        erg = SQLConnect(hOdbc, (SQLCHAR*) "mydb", SQL_NTS,
                        (SQLCHAR*) "user", SQL_NTS,
                        (SQLCHAR*) "pass", SQL_NTS);
        if (CheckSQLHandle (SQL_HANDLE_DBC, hOdbc, erg, "Database Connect"))
        {
                SQLFreeHandle(SQL_HANDLE_DBC, &hOdbc);
                SQLFreeHandle(SQL_HANDLE_ENV, &hEnv);
                return 0;
        }

        TryQuery (hOdbc);

        SQLDisconnect(hOdbc);
        SQLFreeHandle(SQL_HANDLE_DBC, &hOdbc);
        SQLFreeHandle(SQL_HANDLE_ENV, &hEnv);

        return 0;
}