释放ACE_Message_Block出错，为什么？谢谢 , ACE网络编程开发|开源框架

pengxiqin 发表于 2009-10-27 00:14:23

释放ACE_Message_Block出错，为什么？谢谢

在下面的代码中，为什么在int QTest::DequeueAllMsgs()函数里调用mb->release();的时候出现内存释放错误！谢谢！代码如下：

文件MQEG1.h
#ifndef __MQ_EG1_H__
#define __MQ_EG1_H__

#include "ace/Null_Condition.h"
#include "ace/Null_Mutex.h"
#include "ace/Message_Queue.h"
#include "ace/Log_Msg.h"
#include "ace/OS.h"

class QTest
{
public:
// Constructor creates a message queue with asynchronism
QTest( int numMsgs );

// Enqueue the number of messages required onto the message queue
int EnqueueMsgs();

// Dequeue all the messages previously enqueued.
int DequeueAllMsgs();

private:
// Underlying message queue
ACE_Message_Queue< ACE_NULL_SYNCH > *mq_;
// Number of message to enqueue
int numMsgs_;
};

#endif // __MQ_EG1_H__

文件MQEG1.cpp

#include "MQEG1.h"

QTest:QTest( int numMsgs )
   : numMsgs_(numMsgs)
{
// Create a message queue of default size.
if ( !(mq_ = new ACE_Message_Queue< ACE_NULL_SYNCH > ()) )
{
   ACE_DEBUG( (LM_ERROR,"Error in message queue initialization\n") );
}
}

int QTest::EnqueueMsgs()
{
ACE_TRACE("QTest::EnqueueMsgs\n");

for ( int i = 0; i < numMsgs_; i++ )
{
   // Create a new message block specifying exactly
   // an underlying data block should be created
   ACE_Message_Block *mb;
   ACE_NEW_RETURN( mb, ACE_Message_Block(ACE_OS::strlen("This is message 1\n")), -1 );

   // Insert data into the message block using wr_ptr
   ACE_OS::sprintf( mb->wr_ptr(), "This is message %d\n", i );

   // Be careful to advance the wr_ptr by the necessary amount.
   mb->wr_ptr(ACE_OS::strlen("This is message 1\n"));

   // Enqueue the message block onto the message queue
   if ( this->mq_->enqueue_prio(mb) == -1 )
   {
         ACE_ERROR( (LM_ERROR, "Could not enqueue on to message queue\n") );
         return -1;
   }

   ACE_DEBUG( (LM_INFO,"EQ'd data: %s\n", mb->rd_ptr()) );
}// end for

// Dequeue all the message
DequeueAllMsgs();

return 0;
}

int QTest:DequeueAllMsgs()
{
ACE_TRACE( "QTest:DequeueAllMsgs\n" );

ACE_DEBUG( (LM_INFO, "No. of messages on Q:%d Bytes on Q:%d \n", mq_->message_count(), mq_->message_bytes()) );

ACE_Message_Block *mb;

// Dequeue the head of the message queue until no more messages are left.
for ( int i = 0; i < numMsgs_; i++ )
{
   mq_->dequeue_head( mb );
   ACE_DEBUG((LM_INFO,"DQ'd data: %s\n", mb->rd_ptr() ));

   // Release the memory associated with the message block
   mb->release();
}

return 0;
}

int main( int argc, char *argv[] )
{
QTest q(5);
q.EnqueueMsgs();

return 0;
}

在用Release释放ACE_Message_Block的时候弹出对话框，提示如下错误。
Debug Error!
Program D:\Ace_Practice\Sample1.exe
DAMAGE: after Normal block(#153) at 0x003FC938

我用的编译器是VC2003.

[ 本帖最后由 pengxiqin 于 2009-10-28 00:45 编辑 ]

wishel 发表于 2009-10-28 14:44:16

ACE_NEW_RETURN( mb, ACE_Message_Block(ACE_OS::strlen("This is message 1\n") + 1), -1 );
别忘记最后的'\0'，做c字串处理的时候要始终提醒自己，尤其是调用到系统的字串处理函数时。

pengxiqin 发表于 2009-10-28 19:12:00

回复 #2 wishel 的帖子

谢谢版主。:handshake

winston 发表于 2009-10-28 21:53:51

wishel 经验老道。有水平和经验的程序员，会自觉的这么干。

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释放ACE_Message_Block出错，为什么？谢谢

回复 #2 wishel 的帖子