CREATE PROCEDURE storedProcedure
(@inParam VARCHAR(MAX), 
 @outParam VARCHAR(MAX) OUTPUT) AS 
BEGIN 
 SET @outParam = @inParam; 
END;

SQLExecDirect(hstmt1, (UCHAR*)"{call storedProcedure(?,?)}", SQL_NTS);

[Microsoft][ODBC SQL Server Driver][SQL Server]Invalid parameter 
2 (''):  Data type 0x23 is a deprecated large object, or LOB, 
but is marked as output parameter.  
Deprecated types are not supported as output parameters.  
Use current large object types instead.

#include <stdio.h>
#include <string.h>
#include <windows.h>
#include <sql.h>
#include <sqlext.h>
#include <odbcss.h>

#define MAXBUFLEN 255

SQLHENV henv = SQL_NULL_HENV;
SQLHDBC hdbc1 = SQL_NULL_HDBC;     
SQLHSTMT hstmt1 = SQL_NULL_HSTMT;

void Cleanup() {
   if (hstmt1 != SQL_NULL_HSTMT)
      SQLFreeHandle(SQL_HANDLE_STMT, hstmt1);

   if (hdbc1 != SQL_NULL_HDBC) {
      SQLDisconnect(hdbc1);
      SQLFreeHandle(SQL_HANDLE_DBC, hdbc1);
   }

   if (henv != SQL_NULL_HENV)
      SQLFreeHandle(SQL_HANDLE_ENV, henv);
}

int main() {
   RETCODE retcode;
   // SQLBindParameter variables.
   SQLCHAR* sParm1 = (SQLCHAR*) "123";
   SQLCHAR sParm2[10] = {0};
   SQLLEN cbParm1 = SQL_NTS;
   SQLLEN cbParm2 = SQL_NTS;

   // Allocate the ODBC environment and save handle.
   retcode = SQLAllocHandle (SQL_HANDLE_ENV, NULL, &henv);
   if ( (retcode != SQL_SUCCESS_WITH_INFO) && (retcode != SQL_SUCCESS)) {
      printf("SQLAllocHandle(Env) Failed\n\n");
      Cleanup();
      return(9);
   }

   // Notify ODBC that this is an ODBC 3.0 app.
   retcode = SQLSetEnvAttr(henv, SQL_ATTR_ODBC_VERSION, (SQLPOINTER) SQL_OV_ODBC3, SQL_IS_INTEGER);
   if ( (retcode != SQL_SUCCESS_WITH_INFO) && (retcode != SQL_SUCCESS)) {
      printf("SQLSetEnvAttr(ODBC version) Failed\n\n");
      Cleanup();
      return(9);    
   }

   // Allocate ODBC connection handle and connect.
   retcode = SQLAllocHandle(SQL_HANDLE_DBC, henv, &hdbc1);
   if ( (retcode != SQL_SUCCESS_WITH_INFO) && (retcode != SQL_SUCCESS)) {
      printf("SQLAllocHandle(hdbc1) Failed\n\n");
      Cleanup();
      return(9);
   }

   // Connect. 
   SQLCHAR connectOutput[512] = {0};
   SQLSMALLINT result;
   retcode = SQLDriverConnect(hdbc1, 
	   NULL,
	   (UCHAR*) "DRIVER=SQL Server;"
		"UID=test;"
		"PWD=test;"
		"DATABASE=test;"
		"SERVER=localhost;",
		(SQLSMALLINT) SQL_NTS
		, connectOutput
		, sizeof(connectOutput)
		, &result
		, SQL_DRIVER_NOPROMPT);

   if ( (retcode != SQL_SUCCESS) && (retcode != SQL_SUCCESS_WITH_INFO) ) {
      printf("SQLConnect() Failed\n\n");
      Cleanup();
      return(9);
   }

   // Allocate statement handle.
   retcode = SQLAllocHandle(SQL_HANDLE_STMT, hdbc1, &hstmt1);
   if ( (retcode != SQL_SUCCESS) && (retcode != SQL_SUCCESS_WITH_INFO) ) {
      printf("SQLAllocHandle(hstmt1) Failed\n\n");
      Cleanup();
      return(9);
   }

   // Create the stored procedure. 
   retcode = SQLExecDirect(hstmt1, (UCHAR*)"CREATE PROCEDURE storedProcedure(@inParam VARCHAR(MAX), @outParam VARCHAR(MAX) OUTPUT) AS "
		"BEGIN "
		"SET @outParam = @inParam; "
		"END;", SQL_NTS);
   if ( (retcode != SQL_SUCCESS) && (retcode != SQL_SUCCESS_WITH_INFO) ) {
      printf("SQLExecDirect Failed\n\n");
      Cleanup();
      return(9);
   }

   // Bind the return code to variable sParm1.
   retcode = SQLBindParameter(hstmt1, 1, SQL_PARAM_INPUT, SQL_C_CHAR, SQL_LONGVARCHAR, 3, 0, sParm1, 0, &cbParm1);
   if ( (retcode != SQL_SUCCESS) && (retcode != SQL_SUCCESS_WITH_INFO) ) {
      printf("SQLBindParameter(sParm1) Failed\n\n");
      Cleanup();
      return(9);
   }

   // Bind the output parameter to variable sParm2.
   retcode = SQLBindParameter(hstmt1, 2, SQL_PARAM_OUTPUT, SQL_C_CHAR, SQL_LONGVARCHAR, 10, 0, sParm2, 0, &cbParm2);
   if ( (retcode != SQL_SUCCESS) && (retcode != SQL_SUCCESS_WITH_INFO) ) {
      printf("SQLBindParameter(sParm2) Failed\n\n");
      Cleanup();
      return(9);
   }

   // Execute the command. 
   retcode = SQLExecDirect(hstmt1, (UCHAR*)"{call storedProcedure(?,?)}", SQL_NTS);
   if ( (retcode != SQL_SUCCESS) && (retcode != SQL_SUCCESS_WITH_INFO) ) {
	   SQLSMALLINT count = 0;
	   SQLSMALLINT messageLength = 0;
	   SQLCHAR sqlState[SQL_SQLSTATE_SIZE + 1];
	   SQLCHAR message[SQL_MAX_MESSAGE_LENGTH];
	   SQLINTEGER   nativeError;

	   while(SQL_SUCCEEDED(SQLGetDiagRec(SQL_HANDLE_STMT, 
			hstmt1, 
			++count, 
			sqlState, 
			&nativeError, 
			message, 
			sizeof(message), 
			&messageLength)))
	   {
			printf("%s\n\n", message);
	   }
      Cleanup();
      return(9);
   }

   // Show parameters are not filled.
   printf("Before result sets cleared: RetCode = %d, OutParm = %d.\n", sParm1, sParm2);

   // Clear any result sets generated.
   while ( ( retcode = SQLMoreResults(hstmt1) ) != SQL_NO_DATA )
      ;

   // Show parameters are now filled.
   printf("After result sets drained: RetCode = %d, OutParm = %d.\n", sParm1, sParm2);

   // Drop the procedure. 
   retcode = SQLExecDirect(hstmt1, (UCHAR*)"DROP PROCEDURE storedProcedure;", SQL_NTS);
   if ( (retcode != SQL_SUCCESS) && (retcode != SQL_SUCCESS_WITH_INFO) ) {
      printf("SQLExecDirect Failed\n\n");
      Cleanup();
      return(9);
   }

   // Clean up. 
   SQLFreeHandle(SQL_HANDLE_STMT, hstmt1);
   SQLDisconnect(hdbc1);
   SQLFreeHandle(SQL_HANDLE_DBC, hdbc1);
   SQLFreeHandle(SQL_HANDLE_ENV, henv);
}